■n 




Glass- 
Book- 



CATECHISM 



CHEMISTRY 



ADAPTED TO THE COURSE OF LECTURES DELIVERED 



UNIVERSITY OF PENNSYLVANIA. 



BY ISAAC S. HAINBS, HI. D. 



T H I R D JB^I T^LO N 




PHILADELPHIA : 
PUBLISHED BY J. G. AUNER, 

No. 333 Market Street. 

1845. 



Entered according to act of congTcss. in the year 1S44, by Isaac S. 
HAI^"ES, M. D., in the clerk's office of the district court of the United 
States for the eastern district of Pennsylvania. 



-€ 



^44 



Philadelphia : 

T. K. & P. G. Collins, Printers, 

No. 1 Lodge Alley, 



PREFACE, 



Such is the importance to which chemistry has attained, in 
its practical adaptation to all avocations of life, that ignorance 
of its general principles, among" the members of ordinary occupa- 
tions, has become almost inexcusable, and much less so with 
the student of any branch of science. 

The neglect which it has heretofore received from those 
preparing themselves for the practice of medicine, is very great 
and it is difficult to conceive how an individual, whose duty 
consists in ministering to the ever varying diseases of the 
human frame, can possibly call himself a proficient in the heal- 
ing art, who remains ignorant, or imperfectly versed in a sci- 
ence, the principles of which enter so largely into a proper 
knowledge of the modus o^^randi of his prdlession. 

It is not the mere faculty of retaining in the memory what 
is said in public lectures, that changes a student into the useful 
and practical physician. He must make close investigations 
for himself— he must become thoroughly acquainted with the 
principles of every branch of his science — he must learn the 
constituents of every potion he administers ; the separate and 
combined action of each ingredient on the system — before he 
can be properly prepared to fulfil the high and responsible 



station which he assumes, with dignity and honour to himself 
and with advantage to society. By these means only can he 
ever expect to occupy a permanent and elevated station among 
the members of his profession. 

This little contribution is offered to the student of medicine 
with all diffidence; with the contemplation that it may form 
what is so much wanted in chemistry — a stepping stone to the 
more enlarged views and doctrines embraced in our standard 
works on this science. The better to subserve this purpose, as 
well as to enable the author to give it a degree of condensation 
which could not otherwise be attained, the form of a catechism 
has been adopted throughout the volume. From this cause, the 
language may occasionally appear rather uncouth; but this, at all 
times, is preferable to verbosity. The compendium of lectures 
by Dr. Hare has been assumed as its basis, and the order and 
improved nomenclature of that distinguished chemist adhered 
to as nearly as possible. 

The author makes no pretensions to originality ; he asks only 
for the credit of giving a very condensed and correct compila- 
tion from the wor^s of our most approved writers. And with 

4 

the hope that it may be useful in its sphere, he begs leave to 

offer it to the students of medicine, in our different schools, to 
whom it is most respectfully inscribed. 



PREFACE TO THE THIRD EDITION. 



The third edition of the Catechism being called for, I have 
been induced, in compliance therewith, to place the following- 
revision in the hands of the publisher. In contemplating the 
present brilliant epoch in the history of chemistry, in connection 
with the numerous and valuable accessions of modern time, and 
the consequent improvement in the compendium of lectures by 
Dr. Hare, embracing a variety of new and interesting matter, 
the necessity of a more perfect edition of the present work 
must be apparent. Encouraged by the patronage hitherto 
received, and actuated with a desire to facilitate the labours of 
the medical student, I have, in preparing the present edition, 
used every endeavour for its improvement. To effect this 
object, some alterations have been necessarily introduced in 
different parts of the work; much has been re-written ; and, on 
account of the introduction of a considerable portion of new 
matter, it has been found necessary to enlarge the volume. 
So much of it as relates to organic chemistry, having been 
enlarged and extended so as to embrace a great number of 
newly-discovered organic elements, has been entirely re-writ- 
ten. On this subject no inconsiderable amount of labour has 
been bestowed. Such is the importance which this department 



VI TREFACE TO THE THIRD EDITION. 

of the science has at present attained in its various applications 
that it must necessarily occupy no small share of attention in 
a course of instruction. Brought into more general notice 
through the investigations of Liebig and other distinguished 
chemists of the age, the knowledge of animal and vegetable 
chemistry is now cultivated with a most potent and persevering 
industry. Intimately connected with physiological science, 
very much may yet be expected in the progress of researches 
on this subject, in the explanation of vital phenomena. 

Thus revised and corrected, the present edition will be found 
to contain a very condensed view of the present improvements 
in chemistry and peculiarities in modern nomenclature. And, 
in conforming the Catechism to the order and nomenclature 
adopted in the University of Pennsylvania, it has appeared to 
me that it might not be less advantageously employed in other 
medical schools and institutions of learning. 

In offering to the students in our difft^rent schools this little 
contribution, I cannot but indulge the hope that my endeavours 
have not been altogether ineffectual, and that the object at 
which I first aimed has b'^en in part, if not wholly, attained, 

I. S. H. 



CONTENTS. 



Definition of Chemistry. 13 

Repulsion^ - - - - - - - - ib. 

Caloric, - - - - - - - - -14 

Light, 21 

Attraction, - 22 

Chemical affinity, 23 

Atmospheric pressure, - 25 

Laws of combination, ------ 27 

Specific gravity, - - - - - - - 30 

Simple Inorganic Substances. 32 

Oxygen, - - - - ib. 

Chlorine, - 33 

Bromine, __36 

Iodine, ---------37 

Sulphur, ib. 

Sulphuric acid, - ------- 39 

Sulphurous, ib. 

Selenium, - - - - - - - - - - 41 

Tellurium, - .- - ib. 

^Radicals. 42 

Hydrogen, - - - . - - - - 42 

Chlorohydric or muriatic acid gas, . - - - 44 

Sulphydric acid, - - 46 

Nitrogen, -------- 47 

Compounds of nitrogen and oxygen, „ - - - 48 

Nitric acid, (aqua fortis) 50 

Combustion, - - -- -- - -51 

Acidity, 52 

Alkalinity, - 53 

Ammonia, 54 

Phosphorus, - 56 



Viil CONTENTS. 

I 

Carbon, --------- 85 

Carbonic acid, - - - - - - - - 60 

Oxalic acid, - - 61 

Deuto carbohydrogen, (olefiant gas,) - - - - 62 

Cyanogen, - - - - - - - - 63 

Cyanhydric acid, (prussic acid,) - - . - - 64 

Boron, 65 

Selicon, - - ib. 

Metallic Radicals. 67 

Metals of the earths, ------ 70 

Metals of the alkaline earths, 71 

Metals of the proper alkalies, - - - - - 73 

Metals Proper. 77 

Gold, ib. 

Platinum, - 78 

Osmium, --- 79 

Palladium, ib. 

Silver, ib. 

Mercury, --------. 80 

Copper, - -87 

Lead, - - - - 89 

Tin, 91 

Bismuth, 92 

Iron, ib. 

Zinc, - - - - 95' 

Arsenic, 96 

Antimony, 99 

Metals Proper of Minor Importance. 106 

Nickel, - - - ib. 

Chromium, ib. 

Cobalt, ib. 

Manganese, -------- 107 

SALTS. ib. 

Chlorates, 108 



CONTENTS. IX 

'Nitrates, 109 

Sulphates, - - - ib. 

Phosphates, 110 

Carbonates, Ill 

Chromates, --ib. 

lodates and idobydrates, .-...- ib. 
Arseniates, - - - - - - - -112 

Sulphohydrates, ib. 

ORGANIC CHEMISTRY. 114 

Vegetable Substances. ib. 

Amide, - - - - - - - - - 116 

Benzule, - - -117 

Cinnamyle, - - - - - - - - ib. 

Salicyl^ - - - - - - - - ~ ih. 

Ethyl, . i/;. 

Acetyl, - - - - - - « - - 118 

Mesityl, - - - i6. 

Kacodyl, --,-,„.„ i^. 

Methyl, ... = ....- ]]9 

Nutritious Vegetable Substances devoid of Nitrogen, ib. 

Gums, --.-..--- i5. 

Sugars, - - - - - - - - o 120 

Starch or fecula, - - - - - - ^ ib. 

Diastase, - . - 121 

Dextrine, - - - - - -, . - ib. 

Lignin, - - = - . . . , . ib. 

Vegeto-Animal Substances. 122 

Gluten, - - i6. 

Vegetable albumen, --..... i6. 

Vegetable Jibrine, - - - - . . - ib. 

Legumen or vegetable caseine, • ^ ^ . ^ ib. 

OILS. 123 

Olein, - . - . i6. 

Stearine, - - . - - . - - - 124 



X CONTENT.^. 

Margarine, - 1 124 

Spermaceti, . - ib. 

Oil of turpentine, - - 125 

Camphor, ..------.i6. 

Kreosote, - 126 

Resins, .'- - - ib. 

Wax, ib. 

Caoutchouc, - - - - - - - - 127 

Balsams, - - •* ib. 

Gam resins, - - - - - - - - ib. 

ACIDS. 128 
Acetic acid, - --. -.-_-i6. 

Pyroligneous, 129 

Lactic, - - _ ib. 

Citric, - - ib. 

Malic, --„..-.-_i6. 

Tartaric, - - - ~ ib. 

Tannic, - 130 

Gallic, --- ib. 

Meconic, ib. 

Formic, - - - - 131 

Benzoic, - - - ' ib. 

SulphO'Vinic, - - - - - . . - i6. 

Uric, - 132 

ORGANIC VEGETABLE AKALIES. 132 

Morphia, ib. 

Codeia, - - 133 

Narcoiina, - - - ib^ 

Narceia, - - - - - - - - -134 

Quinia, - - - -- - - - - ib. 

Cinchonia, - - - 135 

Aricina, - - ib. 

Strychnia, - - - - - - - . ih- 

Brvcia, ib. 



CONTENTS. XI 

Delphia, - - - - - - - - -13.5 

Veratria^ ... > - - _ - . ih, 

SabadiUa, . - - - ih. 

Jervina^ - - - 136 

Colchicina, ..-.-.,. ib. 

Emeiia^ - - * - - ib. 

Solania^ .-.-..--- 26, 

Caffeia, - - - ib. 

Atropia, .« - - - ib, 

Aconitia, ib. 

Belladonia^ - ib. 

Daturia, - . . ih. 

Conina, ,--...--- z6. 

Picrotoxia, - ib. 

Antiaria * 137 

Thiasinnmnina^ ib. 

Salicine, -- ib. 

ETHERS. 137 

Oxide of ethel, - - - - - - - - 138 

Etherinef - - - - ib. 

Oilofwine^ - - . - - - - ~ ih. 

Hoffman's anodyne liquor, - - - - - - 139 

Alcohol or the Hydrated Oxide of Ethel. 139 

. Nitric ether y ] 40 

Sweet spirits of nitre, ...... ih. 

Aldehyde, - ib. 

Methylic ether, 141 

Pyroxylic spirit, - - - - - - - ib. 

Amylic alcohol, - - - - - - - - ib, 

ANIMAL CHEMISTRY. ib. 

Proteine, - 142 

ALBU31EN, --------- ib. 

Fibrin, ■• ib. 

Caseine, - - 143 



COiN TENTS. 



Blood. 1 44 

HcLmatosine^ - - - . . . . • ih, 

Globuline^ - - - - ^ . . , ilj„ 

Osmazome^ -...„..„ i^. 

Gelatin. ib. 

Leather^ - - - . , - . . - 145 

Glue, ---- = .-., io. 

Sise, -•. = , = .... i^. 

Isinglass, • - - i6. 

Chondrino, --».- = „. i^. 

Nervous matter, .-----. i^. 

Bones, - - - - . ... „ 146 

Teeth, - - - ?/>, 

Animal Secretions. ib. 

Saliva, - - - i6. 

Gastric juice, ib. 

Pancreatic juice, ....-.- {h. 

Bile, 147 

Lymph, - - - - ?■/;. 

Mucus, -.-...--- i6. 

Pus, - - - i6. 

Urine, --------- ib. 

Urea^ ib. 

Urinary calculi, - - 148 

Nutrition, - - - - - - - - 149 

Respiration, - - - ib. 

Fermentation, -..----. ib. 

Putrefaction, - - - - - - - - 150 

Electricity. 152 

Galvanic electricity, - - 157 

Electro-magnetism, - - 159 



CHEMISTRY. 



Question. What is Chemistry defined to be ? 

Answer. It is that science which treats of the phenomena 
and operations of nature, which arise from reaction between 
the particles of inorganic matter. 

Q. How is the distinction between Chemistry and the sci- 
ences of Natural Philosophy and Physiology defined ? 

A. Natural Philosophy, in its limited acceptation, is that 
science which treats of those phenomena that arise from re- 
action between masses, or between a mass and particles. Phy- 
siology treats of those operations that arise from reaction be- 
tween the particles of organic matter; while the phenomena 
which arise from reaction between the particles of inorganic 
matter are embraced in the science of Chemistry, 

Q.. How is chemical reaction divided ? 

A. Into attractive reaction, or attraction ; and repulsive re- 
action, or repulsion. 

Q,, Does attractive and repulsive reaction exist in the same 
kind of matter ? 

A. No. Matter is of two kinds ; one, from possessing weight, 
is called ponderable ; the other, not being detected as possessing 
weight, is called imponderable. In the former kind, attraction 
exists ; in the latter, repulsion. 

Q. What is matter defined to be ? 

A. That which has properties. We know nothing of matter 
but by a knowledge of its properties. 

Q, How many kinds of matter may be inferred to exist ? 
2 



14 CATECHISM ON CHEMISTRY. 

A. Three. Because (here has been demonstrated to be at 
least as many innate properties, which cannot belong to the 
same elementary particles. 

Q. What are these properties ? 

A. 1st. The property of imparting a reciprocal attraction, as 
exemplified by gravitation, cohesion, &c., and which resides in 
all ponderable matter; 2d, the property of imparting a recipro- 
cal repulsion, appertaining to caloric, and 3d, the property of 
imparting a limited and contingent attraction, which appears to 
belong to electricity as well as to light. 

Q. Can you enumerate the imponderable bodies? 

A. Electricity, magnetism, caloric, light. 

CALORIC. 

Q. What is the received opinion concerning the nature of 
caloric? 

A. That it is a material, imponderable fluid, the particles of 
which are self-repellent, and also attracted by other matter. 

Q. What is the effect of caloric on bodies? 

A. It produces changes in bulk, and changes in the state of 
aggregation. 

Q. What change does it produce in the bulk of bodies? 

A. It expands them. 

Q. What change does it produce in the state of aggregation 
of bodies ? 

A. It counteracts cohesion so as to cause fusion and the 
aeriform state. 

Q. What happens to caloric during the process effusion? 

A. It is absorbed without producing any sensible change in 
the temperature of the body, in which state it is called latent 
heat. 

Gl. How much caloric disappears or becomes insensible dur- 
ing the melting of ice ? 

A, By taking equal portions of ice and water, the former at 



CATECHISM ON CHEMISTRY. 15 

the temperature of 32^, the latter at the temperature of 172°, 
the ice will be melted, and the resulting temperature will not 
be a mean, but 32°, thus showing a loss of 140°, which the ice 
required in melting. 

Q. Is the melting or fusing point the same for all substances ? 

A. No. Ice melts at 32°, mercury freezes at 39° below zero, 
and alcohol has not been frozen, 

Q. What is meant by the boiling point ? 

A. That point of temperature at which a liquid assumes the 
gaseous state. 

Q. Is the boiling point the same for different liquids? 

A. No. Water boils at 212°, alcohol at 176^ aether at 98°, 
and mercury at 656°, 

Q. Does water grow hotter after it boils ? 

A. No. The principle which the fire communicates is car- 
ried off in the steam. 

Q. How much caloric is absorbed in producing steam ? 

A. Near a thousand degrees. 

Q. What are the properties of steam ? 

A. It is an elastic invisible fluid, expanded by caloric, and 
condensed into water by cold. 

Q. What influences the boiling point of liquids ? 

A. The pressure of the atmosphere. Water boils in vacuo 
at 72°, alcohol at 36°, and sether would be aeriform were it not 
for the pressure of the atmosphere, thus proving that a liquid is 
not necessarily hot because it boils. 

Q. What advantage has been taken of the fact, that atmo- 
spheric pressure influences the boiling ? 

A. To ascertain the height of mountains ; for every 530 feet 
ascent the boiling point of water is lowered one degree. 

Q. Why is it that the application of cold will cause boiling 
in a matrass which contains steam and water ? 

A. In consequence of the condensation of the steam, the 
pressure which opposes the boiling is removed, and ebullition 
ensues. 



16 * CATECHISM ON CHEMISTRY. 

Q. Are all solids equally expansible by heat? 

A. No. Metals are the most expansible solids, but some 
metals are more expansible than others. 

Q. Is there any exception to the law that solids expand by 
heat ? 

A. No. The fact that ice and certain metals, in fusing-, con- 
tract, are not exceptions to the rule as applied to solids. Clay 
is a supposed, but not a real exception. 

Q. Are liquids as expansible as solids ? 

A. Yes, more so ; but some liquids are more expansible than 
others. Thus, alcohol expands more than water, and water 
more than mercury. 

Q. Do liquids expand equally at all temperatures? 

A. No. They expand in an increasing ratio. Dalton con- 
ceives that the expansion observes the ratio of the square of the 
temperature, estimated from the point of congelation. 

Q. Is there any exception to the law that liquids expand by 
heat? 

A. Water under 39® expands as it grows cold, and in freez- 
ing increases in bulk nearly one-tenth, thus affording a pro- 
vision for aquatic animals. 

Q. What is the cause of the expansion of water at the mo- 
ment of freezing ? 

A. The new arrangement of its particles. 

Q. Do gases expand by heat? 

A. Yes ; they are the most expansible bodies. 

Q,. What peculiarity is there in the expansion of gases? 

A. They expand equally by the same additions of caloric 
and the same gas expands uniformly at all temperatures. 

Q. What is the rationale of expansion ? 

A. That as the caloric combines with the particles of matter 
they acquire its self-repellent power, so as to oppose the force 
of cohesion; hence, those bodies which are held together by a 
feeble affinity are most expansible. 

Q. By what means can we measure the intensity of heat? 



CATECHISM ON CHEMISTRY. , 17 

A. By estimating the degree of expansion which substances 
undergo when subjected to its influence. Vhe instruments 
employed are called thermometers and pyrometers. 
Q. Who invented the thermometer? 

A. Sanctoria. He employed as a thermometric substance 
atmospheric air inclosed in a matrass inverted over water. 
Q. Why was Sanctoria's air thermometer objectionable? 
A. Because it was influenced by atmospheric pressure as 
well as temperature. 

Q. Have solids ever been employed to measure heat? 
A. Yes : clay has been used in Wedgwood's pyrometer. 
Q. In what state of cohesion are bodies best for estimating 
the quantity of heat ? 

A. Liquids; because solids expand too little, requiring a 
complicated machinery to be measured, and gases expand too 
much. 

Q. What liqujds are used ? 
A. Mercury and alcohol. 

Q. Which is the best thermometric substance ? 
A. Mercury; because its expansions are uniform, and its 
boiling and freezing points are very remote from one another. 
Q. For what purpose is alcohol adopted as a thermometric 
substance ? 

A. To ascertain very low temperatures, as it has not been 
frozen. 

Q. How do we measure the exact point of temperature ? 
A. By means of a scale attached to the tube of the ther- 
mometer, with the intervals between the freezing and boiling 
points of water, divided into any number of equal parts or de- 
grees. 

Q. Do all thermometers correspond in the number of divi- 
sions or degrees of the scale? 

A. No. Fahrenheit's scale, the one used in the United States 
and Great Britain, consists of 180, Celsus' of 100, and Reau- 
2* 



16 CATECHISM ON CHEItllSTRY. 

mur's of 80 equal parts, preserving a relation of 9 : 5 : : 4 to 
each other. The point of beginning is called zero. 

Q. In what respect does the zero of Fahrenheit' thermome- 
ter differ frsm others ? 

A. Instead of being at the freezing point of water, it is placed 
at 32° below that point, which makes his boiling point at 212°. 
Q. What is the self-registering thermometer ? 
A. It consists in a mercurial and spirit thermometer, used 
for determining maximum temperatures. 
Q. What is a differential thermometer ? 
A. It consists of a tube bent twice at right angles, having 
some resemblance to the letter U, used for ascertaining the 
difference in the temperature of the same medium. 

Gl. Does the thermometer indicate the quantity of heat con- 
tained in bodies ? 

A. No. It only is affected by the sensible heat or free caloric 
expressed by the word temperature. 

Q. What is meant by the term capacity for heat ? 
A. The relative quantities of caloric required to raise equal 
weights or bulks of different bodies to the same temperature; 
This difference in bodies has been called specific heat. 

Q. What ensues when the capacity of a body for heat under- 
goes a change ? 

A. A change in the temperature of the surroundingjuedium. 
If the capacity be diminished, heat is produced^ if increased, 
the phenomena of cold ensue. 

Q. By what means are the capacities of bodies diminished, 
and heat consequently excited ? 

A. 1st, by diminution of their bulk ; 2d, by chemical agency; 
3d, and by certain changes in their state of cohesion. 

Q. How is it illustrated that diminution of bulk causes the 
evolution of caloric ? 

A. In condensing the atmosphere by means of a condenser 
we can ignite spunk or tinder, and by active percussion of any 



CATECHISM ON CHEMISTRY, 19 

hard body, by which its particles are approximatedj heat is pro- 
duced, 

Q.tWhat are examples of heat being produced by chemical 
means? 

A. 1st, combustion; 2d, simple combination, as the union of 
tin or lead with platina, alcohol and water, sulphuric acid and 
water ; 3d, chemical combination, attended with decomposition, 
as the explosion of gunpowder ; 4th, solution, as nitric acid 
acting on tin. 

Q. What change in the state of aggregation of bodies is 
attended with evolution of caloric ? 

A. Gases becoming liquids, and liquids congealing or be- 
coming solid. 

Q. What is cold defined to be 1 

A. Negative heat. 

Q. How is cold produced ? 

A. By the capacities of bodies for heat being increased, so 
that they extract it from the surrounding bodies. 

Q. Why does cold and cloudiness arise from rarefaction ? 

A. Because the capacity of air for heat is increased, and the 
consequent production of cold condenses the aqueous vapour. 

Q. What are the chemical means of producing cold? 

A. By solution of some of the salts, as nitre and nitrate of 
ammonia, sulphuric acid in dissolving snow, &c. Cold is pro- 
duced when solids melt, and when liquids become aeriform. 

Q. In what three modes is caloric communicated ? 

A. By the process of radiation, conduction, and circulation. 

Q. What is meant by radiant heat? 

A. Heat communicated in right lines in all directions from 
heated bodies. The mode in which our rooms are heated by 
common fire places is a familiar example. 

Q. What influences the radiant power of heat? 

A. The nature of the radiant body, and the colour of the dif- 
ferent surfaces of the same body. 

Q. What kind of bodies are best for radiation ? 



20 CATECHISM ON CHEMISTRY. 

A. Substances which possess porosity ; as charcoal, wood, 
earthenware, &c. Dark-coloured surfaces are most favourable 
for radiating heat. ^ 

Q. When the rays of heat fall upon a body, what becomes 
of them ? 

A. According as the body is more or less porous, they are 
either absorbed or reflected. The absorption of caloric is in- 
versely as its reflection. For this reason it is that the best ab- 
sorbers are the worst reflectors, and vice versa. 

Q. What class of bodies are good reflectors ? 

A. The metals. Because the particles are so nearly ap- 
proximated to each other, or united with caloric, as to leave no 
passage for radiant heat. 

Q. Wiiat are good retainers of heat ? 

A. Metallic bodies, for the same reason that they are good 
reflectors. Hence good radiators are good absorbers, and good 
reflectors are good retainers. 

Q. Why is a bright metallic tea-pot preferable ? 

A. Because it is a good retainer of heat. 

Q. In what kind of bodies is the conducting power predomi- 
nant? 

A. In solid substances, by which caloric is comrilunicated 
from atom to atom. 

Q. What solids are the best conductors of heat ? 

A. The metals. Gold, silver and copper are the best, and 
lead is very inferior. 

Q. Can you enumerate some of the bad conductors ? 

A. Bones, ivory, porcelain, glass, wood, charcoal, silk, cotton, 
wool, (&C, 

Q. Do liquids conduct heat ? 

A. Their power for conducting heat is very imperfect. 

Q. By what mode do liquids become heated ? 

A. That of circulation, which implies a free interchange of 
particles. Heal can only be communicated upwards in a liquid, 
in consequence of its nonconducting power. When heat is 



CATECHISM ON CHEMISTRY. * 21 

applied to the bottom of a vessel containing water, the lower 
particles of the liquid expand, and in consequence of their 
levity, are compelled to ascend to give place to the colder par- 
ticles, which, in consequence of their weight, descend, and 
thus a constant circulation is kept up. 

Q. Can you enumerate some of the proximate sources of 
heat ? 

A. The sun, electricity, collision, percussion, friction, attri- 
tion, chemical agency, fermentation, vitality, &c. 

Q. What are the three states in which caloric exists in na- 
ture? 

A. 1st, As sensible heat, in which it is susceptible of detec- 
tion by the senses or by the thermometer ; 2d, As latent heat, 
in which it is not susceptible to the above means of detection, 
but influenced by external changes of temperature; 3d, As it 
exists in detonating compounds, such as nitrates, chlorates and 
fulminates, in which peculiar state it is independent of external 
changes of temperature. 

CI. What different opinions have been entertained concerning 
the nature of the cause of heat? 

A. One that it is matter, the other that it is motion. The 
former is the generally received doctrine; the latter is supported 
by Count Rumford and Davy ? 

Q. What fact gives support to the theory of Dav}'-? 

A. The circumstance of heat being produced by friction. 

Gt. What fact furnishes the best evidence of the materiality 
of the cause of heat? 

A. That it can be radiated in vacuo as well as in pleno, and 
collected into a focus. 

LIGHT. 

Q. What is the nature of light? 

A. A material elastic fluid, composed of self-repellent par- 
ticles. 



22 CATECHISM ON CHEMISTRY. 

Q. Is light important as a chemical agent ? 

A. Yes. It is produAive of heat, deoxidizement and other 
chemical phenomena, and is evolved by chemical processes. 
It facilitates the bleaching process, blackens some salts, and 
causes the union of hydrogen gas and chlorine gas to take place 
explosively. 

Q. Can you give some of the curious properties of light? 

A. Like caloric it is capable of being radiated and reflected; 
its rays are susceptible of refraction, polarization and disper- 
sion, displaying various colours. 



ATTRACTION. 

Gt. How is attraction divided ? 

A. Into homogeneous and heterogeneous attraction; the for- 
mer takes place between particles of the same kind of matter, 
the latter between particles of different kinds of matter. For 
instance, a lump of brass has its particles held together as brass, 
by homogeneous affinity, but the particles of copper and zinc, 
which, by their union, form brass, are connected together by 
hetero|;eneous affinity. Homogeneous affinity is frequently 
designated by the terms, attraction of aggregation, attraction 
of cohesion, and heterogeneous attraction, by the term chemical 
affinity. 

Q. Can heterogeneous, like homogeneous attraction, be over- 
come by mechanical means ? 

A. No. We may reduce to powder a compound, but cannot 
separate its constituent elements by any mechanical process. 

Q. When the attraction of aggregation is allowed to take 
place slowly and regularly, what are produced ? 

A. Regular shaped masses, called crystals, 

Q. Is a crystal capable of being reduced to an indefinite 
number of primitive forms '? 



CATECHISM ON CHEMISTRY. 23 

A. No. All crystals have a primitive crystalline form ; ac- 
cording to Haiiy there are six primitive forms. 

Q. Enumerate several modes of obtaining crystals ? 

A. By fusion, followed by congelation, evaporation, precipi- 
tation, and sublimation. 

Q. What is essential to the constitution of crystals ? 

A. Water ; called water of crystallization. Some crystals, 
on exposure to the air, lose, while others gainj water; the 
former property is called efflorescence, the latter deliquescence. 

Q. Enumerate the different states of aggregation ? 

A, There are three, viz : solid, liquid and gaseous. 

Q. What causes overcome cohesion or attraction of aggre- 
gation ? 

A. Solution, heat, and mechanical division. 

CHEMICAL AFFINITY. 

Q. What is chemical affinity ? 

A. It is that attraction by which the particles of dissimilar 
matter are united into a compound. 

Q. What is the characteristic of a chemical compound? 

A. That it partakes of the properties of neither of its con- 
stituent elements, but acquires a new and distinct character. 
Oxygen and nitrogen gas, both harmless ingredients in the air, 
are capable of forming, when united in certain proportions, one 
of the most corrosive compounds — aqua fortis, 

Q. Enumerate some of the phenomena that attend chemical 
action. • # 

A. Changes of density, temperature, state of aggregation and 
colour. 

Q. Are there several cases of affinity ? 

A. Yes. According to Dr. Hare there are four cases. 

Q. Illustrate the first case of affinity ? 

A. It is where two substances unite to form a compound; 



24 CATECHISM ON CHEMISTRY. 

for instance, copper and zinc form brass, acids and alkalies 
form salts. This is called simple combination. 

Q. Illustrate, with an example, the second case of affinity ? 

A. It is when two substances being in union we add a third, 
which unites with one of them to the exclusion of the other, as 
sulphate of magnesia (epsom salt) is decomposed by potash; in 
consequence of the superior affinity of the latter for the sul- 
phuric acid of the sulphate, the magnesia is precipitated. This 
case is called single elective attraction or simple affinity. 

Q. Define, with an example, the third case of affinity ? 

A. It is where two compounds mutually decompose each 
other; as sulphate of zinc, being mixed with acetate of lead, 
forms sulphate of lead and acetate of zinc. This is called 
double elective attraction or complex affinity, 

B. Illustrate, with an example, the fourth case of affinity? 
A. It is where two substances being in union, a third being 

added in excess combines with both; for instances, ammonia, 
on being added in excess to some metallic salts, as those of 
copper or silver, unites both with the acid and the metal. 

Q. Enumerate some of the causes which influence or limit 
chemical action ? 

A. Cohesion, solution, temperature, pressure of the atmo- 
sphere, quantity of matter or relative proportions, and specific 
gravity. 

Q. Can you give an example of the influepce of cohesion as 
an opponent to chemical action ? 

A. If a ball of brass be put into one glass and only half its 
weight of brass filings into another, on adding nitric acid to 
both, a violent effervescence ensues in the one, while in the other 
the reaction will scarcely be discoverable. 

Q. Can you furnish an example of the influence of solution 
over affinity ? 

A. Tartaric acid and a carbonate, pulverized and intimately 
mingled, are observed not to react until moistened, when violent 
action ensues. 



CATECHISM ON CHEMISTRY. 25 

Q. Can an exception be furnished to the rule that fluidity is 
required for chemical action ? 

A. Yes. By mixing slacked lime and muriate of ammonia 
tog-ether in powder, the pungent fumes of ammonia are quite 
observable. 

Q. Can you give an example of the influence of temperature 
over chemical affinity ? 

A. Epsom salts will dissolve only to a certain extent in cold 
water, but when heat is applied the solution will go on still 
further. Some substances, as the alkaline earths, are more 
soluble in cold than boiling water. 

Q. How is the influence of atmospheric pressure over chemi- 
cal affinity demonstrated ? 

A. When a gaseous substance ceases to escape from com- 
bination under ordinary pressure, if that pressure be removed, 
chemical action will again go on, and more of the gaseous mat- 
ter will be extricated. 

Q.. Can an example be furnished of the influence of relative 
proportion or quantity of matter over chemical action ? 

A. Of the three oxides of lead, the peroxide parts most easily 
with its oxygen by the action of caloric, while the protoxide 
will bear the strongest heat of our furnaces without losing a 
particle of oxygen; so that that compound will be the most dif- 
ficult of decomposition which contains the smallest quantity of 
oxygen. 

Q. How do you illustrate the influence of gravity over af- 
finity ? 

A. When metallic bodies are in combination, the heaviest 
metal is not unfrequently found in the bottom of the metallic 
mass. 



ATMOSPHERIC PRESSURE. 

Q. How is it demonstrated that the air is possessed of weight ? 
A. By allowing it to enter an exhausted glass globe while 
3 



26 CATECHISM ON CHEMISTRY. 

accurately counterpoised upon a scale beam, the latter is made 
to preponderate. 

Q. What is the average weight of the air ? 

A. Equal 15 pounds for every square inch. According- to the 
Torricellian experiment, it is demonstrated that the pressure of 
the atmosphere on mercury on the outside of a tube unbalanced 
by the like pressure v^ithin, will cause a column of that liquid 
to be supported at the height of thirty inches. Consequently 
the mercury in the tube is equal to the Vs^eight of the air which it 
balances. To prove the truth of this allegation, it is only ne- 
cessary, by means of an air pump, to remove the pressure on 
the outside of the tube, and the mercurial column unbalanced 
by external pressure subsides. 

Q, How high will the pressure of the atmosphere support a 
column of water in a tube exhausted of air ? 

A. Thirty-three or thirty-four feet. It is upon this principle 
that the water pump operates ; the admission of the atmosphere 
being indispensable, as well as the exhaustion of the tube. A 
column of mercury thirty inches in height will precisely balance 
a like column of water 34 feet. 

Gl. By what means is the pressure of the atmosphere gene- 
rally determined? 

A. By the height at which a column of mercury is sustained. 
The instruments employed are called barometers. The baro- 
metric pressure varies from 28 to 31 ; average 30. 

Q. Supposing the air to be of uniform density throughout, 
can we calculate its height ? 

A. By multiplying the specific gravity of mercury by the 
height at which the mercurial column is supported, will give 
the height of a column of water equal to 34 feet. On the same 
principle we may calculate the height of the air. 

Q. Is the air of uniform density throughout? 

A. As its pressure causes its density, in elevated situations 
density is diminished. At 30 miles height, it is supposed to be 
as rare as can be made by the air pump. 



CATECHISM ON CHEMISTRY. 27 

Q. What influence does the pressure of the atmosphere exert 
over the boiling point of liquids ? 

A. They boil in vacuo 140° Icv^er than in the open air. 
Thus water boils in vacuo at 72°, alcohol at 36°, and aether at 
42° below zero. 

Q. What influence does it exert over chemical action ? 

A. It limits it so as to prevent the escape of gaseous sub- 
stances from combination. 

Q. What other mechanical properties does the air possess ? 

A. It is compressible, elastic, and its specific gravity is made 
unity or the standard of the gases. 

Gt. How can we demonstrate the elastic reaction of air*? 

A. By placing an air-tight bottle on the receiver of an air 
pump, and exhausting the receiver, when the air on the inside 
of the bottle rushes to restore the equilibrium with a force suf- 
ficient to fracture it. 

Q,. What is the difference between the air and water pump ? 

A. The only difference between pumping air and water 
arises from the nature of these fluids; in the former process air 
rushes out by its own elasticity, in the latter water is forced out 
by atmospheric pressure. 

Q. Is the bulk of air subject to change ? 

A. Yes. It is influenced by temperature as well as pressure. 
The resistance of the air is in proportion to its compression. 

Q. Is the air of uniform temperature throughout? 

A. No. It varies with the elevation. It is lessened one de- 
gree for every three hundred feet. 

Q. How is this flict accounted for? 

A. There are two causes. The air receives its caloric from the 
earth, and the rarified air possesses a greater capacity for heat. 

LAWS OF COMBINATION. 

Q. Do the proportions with which one substance combines 
with another, influence the force of attraction ? 



28 CATECHISM ON CHEMISTRY. 

A. Yes, Attraction may be divided into feeble and energetic 
affinity, according as the elements of the compound are united 
in many or few proportions* Feeble affinity is displayed in 
those compounds whose elements are united in many propor- 
tions ; while that class of combinations, the elements of which 
unite in a few proportions only, display an energetic affinity. 

Q. Can you give examples of substances in combination 
which display a feeble affinity? 

A. The union of water and alcohol, and the union of sul- 
phuric acid and water, afford instances in which combination 
takes place in every proportion and without limit. Solution is 
an instance of union in every proportion within a certain limit, 
which limit is the point of saturation. 

Q. Can you give examples of those compounds whose ele- 
ments are united by an energetic affinity, and in few propor- 
tions ? 

A. Chlorine and hydrogen unite in only one proportion ; hy- 
drogen and oxygen in two proportions ; other substances unite 
in three, four and even five or six proportions. This class of 
compounds form the most interesting series, and possess the 
properties of neither of their constituent elements. 

Q. What laws regulate these compounds ? 

A. There are three ; namely — 1st. Bodies unite in definite 
proportions. 2d. They unite in progressive proportion, which 
obey the law of multiples. 3d. They unite in equivalent pro- 
portions. 

Q. What is meant by definite proportions ? 

A. That bodies unite ia fixed and invariable proportions. 
For instance, water is composed of eight parts of oxygen to one 
of hydrogen ; and in no other proportions could these elements 
form water. 

Q. Can you illustrate the meaning of progressive and multi- 
ple proportions? 

A. When substances unite in two or more proportions, the 
several proportions with which one body combines with another 



CATECHISM ON CHEMISTRY. 29 

are in the ratio of I, 2, 3, 4, 5. For instance, oxygen unites in 
the following proportions, with one proportion of nitrogen, viz: 
to form nitrous oxide, 1 atom weighing 8 ; nitric oxide, 2 atoms 
weighing 16; hyponitrous, 3 atoms weighing 24 ; nitrous acid, 
4 atoms weighing 32 ; and nitric acid, 5 atoms weighing 40 — 
thus, 8 being divided into 40, v^ill be a multiple of the whole 
number five without a fraction. This law leads to the atomic 
theory. 

Q. What is meant by equivalent proportions ? 

A. That the number which represents the proportion with 
"which one body is capable of combining with another, is also 
the representative of the proportion in which the same body 
combines with every other ; that is to say, that bodies combine 
in reciprocating ratios. For instance, 8 parts of oxygen unite 
with 1 of hydrogen, with 16 of sulphur and 36 of chlorine ; and 
the 16 of sulphur is the exact quantity for union with 1 of hy- 
drogen and 8 of oxygen, and 36 of chlorine — thus showing 
that the weights of the combining proportions of these bodies 
are equivalent one to another. 

Q. Do the equivalent numbers represent absolute weights ? 

A. No. Only the relative weights of the combining propor- 
tions. 

Q. How is the union of bodies in definite and multiple pro- 
portions accounted for? 

A. By admitting the atomic theory to be correct, which sup- 
poses that the ultimate particles, called atoms, possess in dilFe- 
rent substances different weights; and that when bodies unite, 
it is the atoms which combine with one another. 

Q. What is understood by the theory of volumes 7 

A. It is the relative or equivalent bulks in which bodies 
combine together, called also combining volume. 

Q. As bodies combine in equivalent weight, does it follow 
as a necessary consequence that the equivalent bulks should 
correspond ? 

A. No. For instance, the combining proportion of oxygen 
3* 



30 CATECHISM ON CHEMISTRY. 

is eight times heavier than hydrogen, yet the hydrogen occu- 
pies twice the volume. 

Q. Are the combinations of bodies in volumes like the com- 
bining weights in multiple proportions ? 

A. Yes, According to the hypothesis of Gay-Lussac, sub- 
stances, when seriform, unite in volumes which are equal; or 
that when unequal, the larger volume is double, triple, or 
quadruple the other. The numbers which represent the com- 
bining volumes, do not run as high as those of the combining 
weights. 

Q. What peculiarity is there in the combining bulks of 
gases ? 

A. A great number of them possess the same combining 
volume which indicates an equal magnitude of the atoms. For 
instance, chlorine, hydrogen, nitrogen, carbonic acid and cya- 
nogen, combine in equal volumes. Oxygen possesses only half 
the volume of the above list, while muriatic acid and ammonia 
occupy twice the volume. 

Q. If we call the combining volume of oxygen, unity, what 
is hydrogen and ammonia? 

A. Hydrogen would be two, and the number for ammonia 
four. For convenience, it is best to make that number unity 
in bulk which represents so many gaseous substances. 

Q. Are the combining volumes absolute or relative ? 

A. Rel.ative. Hence it is immateriert what we make the num- 
ber for the combining volumes, so we preserve their relations. 
As nearly all the gases are uniform in combining bulk, it is 
most convenient to make them unity. Thas oxygen would be 
represented by one half a volume, hydrogen and chlorine one 
volume, and ammonia two volumes, as their combining bulks. 

SPECIFIC GRAVITY. 

Q. What is understood by the term specific gravity? 

A. It is the relative weights of equal bulks of different bodies^ 



CATECHISM ON CHEMISTRY. 31 ' 

Q. How is the specific gravity of a body ascertained? 

A. As water is assumed to be the standard or unity, it is only 
necessary to divide the weight of the body by the weight of a 
like bulk of water. 

Q. How is the difficulty of obtaining equality of bulk in 
order to find specific gravities obviated ? 

A. Since a body, when sunk in water, will displace precisely 
its own bulk of that liquid, and as the weight of the bulk of 
water displaced is equal to the resistance which the body en- 
counters in sinking, we have only to divide the weight of the 
body by what it loses of its weight in water, to get the specific 
gravity. 

Q. How do we obtain the specific gravity of a body lighter 
than water? 

A. As the resistance to its sinking in water, added to what 
is necessary to overcome that resistance, is equal to the weight 
of a like bulk of that liquid, we proceed by dividing the weight 
thus obtained into the weight of the body. 

Q. How ascertain the specific gravity of any liquid ? 

A, By dividing the resistance which a body encounters in 
sinking into the liquid in question, by the resistance to its sink- 
ing in water. 

Q. What are hydrometers ? 

A. Hydrometers are instruments for ascertaining the relative 
resistances which different liquids offer to the sinking of a body 
in them, estimated by means of a graduated scale. The gra- 
duation commences at the top of the scale for liquids heavier 
than water, and at the bottom for liquids lighter than water. 

Q. How are obtained the specific gravities of gases*t 

A. By filling a glass globe with any gaseous body, and weigh- 
ing it. As the atmosphere is the unit, we obtain the specific 
gravity of a gas by dividing the latter by the former. 

Q. Why is it that one substance is possessed of more weight 
than another ? 

A. Either because the particles differ in weight, or it is de- 



32 CATECHISM ON CHEMISTRY. 

pendent on the degree of their approximation creating more or 
less interstitial space. 

Q. How does it happen that a pound of feathers is heavier 
than a pound of lead ? 

A. Because when a body is suspended in a fluid it is resisted 
in proportion to the weight of the fluid, and the quantity dis- 
placed by the body. Consequently, the more space it occupies, 
in proportion to its weight, the more will its weight be coun- 
teracted. Hence, on removing atmospheric pressure, the pound 
of feathers will preponderate. 



SIMPLE INORGANIC SUBSTANCES. 

Q, What is the number and classification of the simple 
bodies ? 

A. They are fifty -four in number. They are classified, ac- 
cording to Dr. Hare, into basacigen substances and radicals, 

Q. What is implied by the term basacigen substances? 

A. They are those elements which produce both acids and 
bases, by combining with the remaining elements. 

Q. Enumerate the basacigen substances ? 

A. They are nine in number, as follows, viz: Oxygen, Chlo- 
rine, Bromine, Iodine, Flourine, Cyanogen, Sulphur, Selenium, 
and Tellurium. 

Q. How does Berzelius divide them ? 

A. Into two classes; viz : the Halogen and Amphigen class. 
Chlorine. Bromine, Flourine, and Cyanogen, belong to the 
former, while Oxygen, Sulphur, Selenium, and Tellurium, be- 
long to the latter. 

OXYGEN. 

Q, In what does oxygen gas exist ? 

A. It is a universal constituent of animal and vegetable sub- 



CATECHISM ON CHEMISTRY. 33 

stances. It constitutes one-fifth of the bulk of the air, and one- 
third of the bulk of water. 

Q. Why called oxygen ? 

A. Derived from the Greek word signifyingf to produce acid ; 
from the impression of its being the sole acidifying principle. 

Q. How is it procured ? 

A. By depriving an oxide of its oxygen by heat. On account 
of its cheapness the tritoxide of manganese is used. Other sub- 
stances which, when heated, part with oxygen, may also be 
employed for the purpose, such as nitre, chlorate of potash, &c. 

Q. What are the properties of oxygen ? 

A. It is an insipid, inodorous, colourless, and transparent 
gas, but slightly absorbed by water, combines with bodies 
forming either ordinary oxides, acids, or alkalies, an active 
supporter of combustion, and is an indispensable agent in sup- 
porting life. 

Q. How is its activity as a supporter of combustion proved ? 

A. By its burning sulphur, phosphorus, and intensely that 
of iron wire. The result is sulphurous and phosphoric acids, 
and oxide of iron. 

CHLORINE. 

Q. In what does chlorine exist ? 

A. It constitutes three-fifths of common salt, (chloride of so- 
dium,) forms one-fiftieth of the matter in the ocean, and is dis- 
seminated throughout the land. 

Q. By whom was it discovered ? 

A. Scheele, in the year 1770, made the discovery. He gave 
it the name of deplilogisticated marine acid. 

Q. What was the opinion entertained by the French che- 
mists of the nature of chlorine? 

A. That it was a compound of muriatic acid and oxygen, an 
opinion proposed by Berthollet. Its compound nature was first 



34 CATECHISM OiN CHEMISTRY. 

denied by Sir H. Davy, who ranked it among the simple bodies. 
From its colour, he gave it its present name. 

Q. How is chlorine procured? 

A. There are several modes of obtaining chlorine. It may 
be obtained by the action of muriatic acid on peroxide of man- 
ganese. Muriatic acid is decomposed ; its hydrogen uniting 
with the oxygen of the oxide forms water, and its chlorine 
escapes. Generally procured from chloride of sodium, which 
is heated in a glass or leaden retort, with diluted sulphuric acid 
and peroxide of manganese. The water of the acid is decom- 
posed, the oxygen uniting with sodium to form soda, with which 
part of the acid combines, forming sulphate of soda. The hy- 
drogen of the water is retained by the oxygen furnished from 
the oxide of manganese, while the chlorine alone is allowed to 
escape. 

Q. What are the properties of chlorine ? 

A. It is a permanent gas of a greenish yellow colour, ab- 
sorbed by water, rendered liquid by great pressure, irrespirable, 
capable of exciting the sensation of warmth, and is an active 
supporter of combustion. 

Q. Of what utility is chlorine? 

A. It forms some of the most active medicinal and corrosive 
compounds; it is a powerful disinfecting agent, and very im- 
portant for the purpose of bleaching. 

Q. How do you explain the rationale of its bleaching power ? 

A. Hydrogen of water unites with the chlorine, and the de- 
composition of the colouring matter is occasioned by the oxy- 
gen which is liberated. Hence the presence of water is required 
for bleaching, which is decomposed, and muriatic acid is formed 
by the union of hydrogen and chlorine. 

Q. What are formed by the action of chlorine on the metals ? 

A. Chlorides of metals. It is the only solvent of gold. 

Q. What is its equivalent number and specific gravity ? 

A. Its equivalent is represented by 36 ; its specific gravity 
by 2.5. 



CATECHISM ON CHEMISTRY. 35 

Q. What is the best test for chlorine ? 

A. Silver in solution; which causes a dense white precipitate 
of chloride of silver. 

Q. How many compounds are there of chlorine and oxygen? 

A. Four; namely, hypochorous acid, composed of 1 atom or 
1 volume of chlorine with 1 atom or ^ volume of oxygen ; chlo- 
rous acid composed of 1 atom or 1 volume of chlorine with 4 
atoms or 2 volume of oxygen ; chloric acid, composed of 1 
atom or 1 volume of chlorine with 5 atoms or 2J volumes of 
oxygen ; and perchloric acid composed of 1 atom or 1 volume 
of chlorine with 7 atoms or 3^ volumes of oxygen. 

Q. What are the properties of hypochlorous acid? 

A. Its aqueous solution possesses properties, resembling in 
some degree chlorine. When a gas, it is of the colour of chlo- 
rinCj very absorbable by water, which absorbs an hundred 
time its own volume ; it detonates at an elevation of temperature 
and is explosive. 

B. What are the properties of chlorous acid ? 

A. It is a gas of a deeper yellow colour than chlorine, of an 
aromatic odour; in solution it whitens litmus without reddening 
it; when subjected to the electric spark it explodes violently; 
water absorbs 7 times its volume, and it is capable of liquefac- 
tion when subjected to great pressure. 

Q. What is euchlorine ? 

A. It is supposed to be a mixture of chlorine and chlorous 
acid. 

Q. How is it procured ? 

A. By the action of dilute muriatic acid on chlorate of pot- 
ash. Part of the muriatic acid, by its affinity for the potash, 
disengages chloric acid, which, reacting with the remainder of 
the muriatic acid, results in chlorine and chlorous acid. 

Q. What are the properties of euchlorine ? 

A. It is a gas of a greenish yellow colour, very absorbable 
by water, detonates from the warmth of the hand, &c., occupy- 
ing J more space, and explodes with antimony. 



36 CATECHISM ON CHEMISTRY. 

Q. What are the peculiarities of chloric acid ? 

A. It is an inodorous, colourless, sour and an astringent 
liquid. It does not precipitate solutions of lead, mercury or 
silver, and is easily decomposed. 

Q. What are the peculiarities of oxychloric or perchloric acid? 

A. It is a limpid, colourless liquid, having a lively acid taste. 
It reddens but does not bleach an infusion of litmus, and is of 
difficult decomposition. 

BROMINE. 

Q. Where is Bromine found to exist ? 

A. In sea water in the state of bromohydric acid, combined 
with magnesia as a bromohydrate. As such it is found in the 
waters of the Dead Sea and in the salt springs of Germany. 

Q. How is it procured ? 

A. By passing chlorine into sea water. The chlorine unites 
with the hydrogen, which produces muriatic acid, and we have 
muriate of magnesia formed, and a solution of bromine dis- 
placed. Then wash the solution with SBther, and treat the 
SBtherial solution with potash, which results in bromide of 
potassum, from which bromine is obtained precisely as chlorine 
is from the chloride of sodium. 

Q. Can you give the properties of bromine? 

A. It is a liquid of a dark reddish colour, very volatile, in 
odour like chlorine, absorbed by water, alcohol and aether; 
boils at 89° and freezes at a temperature of from 7° to 12° be- 
low zero ; it extinguishes flame, does not conduct electricity, its 
specific gravity 2.966, and in other respects resembles chlorine, 
both as it regards its habitudes and its effects upon organic pro- 
ducts. When taken internally it is a virulent poison. 

Q.. What are the compounds with bromine? 

A. With oxygen it forms bromic acid, with hydrogen bromo- 
hydric acid, and with metals, bromides. 

Q. How is bromine in most cases detected ? 



CATECHISM ON CHEMISTRY, * 37 

A. By means of chlorine, which displaces it from its combi- 
nations. 



IODINE. 

Q. By whom and when was iodine discovered ? 

A. By Courtois, a manufacturer of saltpetre at Paris, in the 
year 1812. 

Q. Where has it been found to exist ? 

A. In sea plants, especially common sponge, and in mineral 
waters, and, according to Dr. Steel, it is found in those of Sara- 
toga. 

Q. How is it .obtained ? 

A. By the action of heat and sulphuric acid on the residue 
that is left in manufacturing carbonate of soda from kelp. It 
comes over in a beautiful violet vapour. 

Q. Can you give the properties of iodine ? 

A. It is a solid of a bluish-black colour, acrid,, and stains 
the skin yellow. It is a crystalline powder, fusible at 225 
degrees, and volatilized at 350; it is not combustible in oxygen 
or the air, and almost insoluble in water. Equivalent, 124. 
Specific gravity 4.946 nearly 5. Taken internally it is poison- 
ous, 

d. What are solvents of iodine ? 

A. Alcohol and aether. 

Q. What is the best test for iodine ? 

A. Starch, with which it forms an intense blue colour. 

Q. What are some of the compounds of iodine? 

A. With oxygen it forms iodic ; with chlorine, chloriodic ; 
with hydrogen, idohydric acid, and with metals it forms iodides, 

SULPHUR. 

' Q. In what state does sulphur exist in nature ? 
4 



38 CATECHISM ON CHEMISTRY. 

A. It is found pure, and widely disseminated in combination 
with metals, as a sulphide. 

Q. In what kind of countries does it occur as native 
sulphur ? 

A. In the vicinity of volcanoes. The most common mines 
are in Naples, Sicily, and the Roman states. 

Q. How is sulphur obtained ? 

A. By the application of heat to crude sulphur, or to some of 
the sulphides, by which it is either fused and run into moulds 
constituting^ what is called roll sulphur, (brimstone,) or sub- 
limed, forming the flowers of sulphur. 

GL What are the properties of sulphur? 

A. It is a solid, of a pale-yellow colour, when sublimed; of a 
crystalline structure, nearly insipid, inodorous unless when 
rubbed or heated; rendered electric by friction, is a bad con- 
ductor of heat, very volatile, being capable of undergoing a 
slow combustion at 180 degrees, and soluble in boiling oil of 
turpentine. 

Q. When subjected to certain temperatures, what peculiar 
changes does sulphur undergo ? 

A. At 180° it volatilizes, at 225° it melts, between 350° and 
400° it thickens, when exposed to 560° it takes fire, but if con- 
fined in close vessels at 600° it sublimes. 

Q. Does sulphur support combustion ? 

A. An iron wire burns in it, forming sulphide of iron. 

Q. In what form is sulphur sold in shops ? 

A. As rolls, flowers, and precipitated or Lac sulphuris. 

Gt. How is Lac sulphuris obtained? 

A. By precipitation of sulphur from a solution of sulphuret of 
lime, made by boiling sulphur and lime together by means of 
an acid. The ac^d, by uniting with the alkali, precipitates the 
sulphur as a hydrate. 

d. Will any acid answer equally w^ell ? 

A. Muriatic acid should be used, because the muriate of lime 
is soluble. Other acids from forming insoluble salts with lime, 



CATECHISM ON CHEMISTRY. 39 

should not be used, as they would be precipitated with the sul- 
phur. 

Q,. How can crystals of sulphur be formed'? 

A. By fusion followed by congelation. 

Q. With what does sulphur combine ? 

A. Oxygen, chlorine, iodine, bromine, hydrogen, metals and 
metallic oxides, &,c. 

Q. What are the compounds of sulphur and oxygen ? 

A. Sulphuric, hypo-sulphuric, sulphurous, and hypo-sulphu- 
rous acid. 

Q. How is sulphurous acid obtained ? 

A. By the ordinary combustion of sulphur, or by boiling 
sulphuric acid on sulphur, mercury, or any deoxidizing agent. 

Q. What are the properties of sulphurous acid? 

A. It is a gas, irrespirable — does not support combustion, 
bleaches silk and wool, whitens litmus, and is very absorbable 
by water. 

Q. What is the atomic composition of this gas? 

A. One atom of sulphur with two of oxygen. 

SULPHURIC ACID. 

Q. How is sulphuric acid obtained ? 

A. By burning sulphur and nitre over a stratum of water in 
chambers lined with lead ; or by the old process of distilling 
green vitriol. 

Q. How do we explain the rationale for obtaining sulphurilP 
acid by burning sulphur with nitre ? 

A. The nitric acid of the nitre yields three atoms of oxygen 
to a portion of sulphur, and converts it into sulphuric acid 
which combines with the potash of the nitre ; while the greater 
part of the sulphur forms sulphurous acid by uniting with the 
oxygen of the air. The nitric acid, in lo.sing three atoms of 
oxygen is converted into nitric oxide, which, by mixing with 



40 CATECHISM ON CHEMISTRY. 

air, gives rise to nitrous acid red fumes. By the assistance of 
aqueous vapour, a white crystalline compound is formed, which 
is composed of water and the two acids. This crystalline solid 
is decomposed by the water at the bottom of the chamber into 
sulphuric acid and deutoxide of nitrogen, and the latter meet- 
ing- with the air of the chamber takes oxygen, and becomes 
again nitrous acid. As the process goes on, by the aid of heat 
and air, more nitrous and sulphurous acid is formed, which, 
combining with the aqueous vapour, results in the formation of 
more of the crystallized compound, which, being decomposed 
again, more sulphuric acid and nitric oxide continue to be 
formed. 

QL, What is the alleged composition of this crystalline solid? 

A. Two atoms of sulphuric acid, with one atom of nitrous 
acid, and a small quantity of water. This composition is in- 
ferred from the fact, that the quantity of oxygen required to 
convert the two equivalents of sulphurous lYito sulphuric acid, 
is precisely that which one equivalent of nitrous acid loses in 
being converted into nitric oxide. 

Q. What are the properties of sulphuric acid ? 

A. It is an oleaginous, heavy liquid, coloured, and almost 
without odour when pure, caustic when concentrated, intensely 
acid when diluted; has a strong affinity for water; with hot 
water it explodes, and it exceeds all acids in its power of red- 
dening litmus. 

Q. What happens to it when exposed to the air? 
IP A. It is diluted, in consequence of the absorption of moisture 
from the air. 

Q. What effect is produced when mixed with water in cer- 
tain proportions ? 

A. A remarkable elevation of temperature. When three 
parts are added to one of water, a boiling heat is produced. 

Q. What is the best test ? 

A. Baryta, forming the insoluble sulphate of baryta. 

Q. What is the composition of sulphuric acid? 



CATECHISM ON CHEMISTIIY. 41 

A. One atom of sulphur to three atoms of oxygen, 

Q, What is the old name for this acid? 

A. Oil of vitriol, from the circumstance of its being obtained 
from green vitriol. 

Q. In v?hat respect does the sulphuric acid of JSordhausen 
differ from that in common use ? 

A. In containing a portion of acid free from water called 
anhydrous. 

Q. What are the peculiar properties of this? 

A. It is solid, crystalline, of a waxy consistence, emitting 
thick fumes in the air, liquifies at 64*^; when vapourizing, 
forms a colourless gas and is of use for the solution of indigo em- 
ployed in dyeing. It is called the fuming acid of Nordhausen. 

Q. What is selenium ? 

A. A newly discovered substance, its properties being inter- 
mediate to sulphur and the metals, and is found in volcanic 
rocks, in union with them. 

Q. What are the properties of selenium ? 

A. It is a solid, of a lead colour, insipid, a bad conductor of 
heat and electricity, and is not rendered electric by friction. 
Heated before the blowpipe, it tinges the flame of an azure 
blue, and emits the smell of horseradish. 

Q. Are there compounds of selenium? 

A. Yes. There is an oxide, acid, a chloride, and a compound 
with hydrogen. 

Q. Where is tellurium found ? 

A. It is a very rare substance, found in the mines of Tran- 
sylvania. 

Q. What are the striking properties of tellurium ? 

A. It is a bright tin colour, fusible below a red heat, and 
volatile above that point; heated before the blowpipe, it burns 
with a greenish blue flame, and forms compounds with oxygen 
and hydrogen. 



4* 



42 CATECHISM ON CHEMISTRY. 



RADICALS. 

Q. What are radicals defined to be ? 

A. Radicals are bodies capable of forming, with abasacigen 
body, either an acid or a base, or both, and which do not form 
acids or bases with each other, 

Q. Enumerate the nonmetallic radicals. 

A. Hydrogen, nitrogen, phosphorus, carbon, boron, silicon, 
and zirconion. 



HYDROGEN. 

Q. In what does hydrogen exist ? 

A. In water; and it is a principal constituent of ordinary 
flame. 

Q. How is hydrogen procured ? 

A. By the decomposition of water, either by passing steam 
over turnings of iron made red hot in a gun barrel, or by the 
reaction of dilute sulphuric or muriatic acid on turnings of iron 
or zinc. In the former case, the oxygen combines with the 
metal, while the hydrogen escapes ; in the latter, the water of 
the sulphuric acid is decomposed; the oxygen oxidizes the 
metal, with which the acid combines to form a salt, while the 
hydrogen escapes. 

Q. What are the properties of hydrogen? 

A. It is, when pure, an insipid, inodorous and colourless 
gas, never rendered liquid, does not support life, nor combustion 
— it is pre-eminently inflammable, and possesses a high capa- 
city for heat, sparingly absorbed by water — and it is the lightest 
of all ponderable substances. The equivalent of hydrogen is 
unity. 

Q. If mixed with oxygen, or atmospheric air, in certain pro- 
portions, and subjected to the electric spark, what happens ? 



CATECHISM ON CHEMISTRY. 43 

A. It explodes. The hydrogen to the oxygen must be in 
the proportion of two to one to form an explosive mixture. 

Q. What are some of the compounds of hydrogen? 

A. With oxygen it forms water ; with chlorine, chlorohydric 
acid ; with iodine, idohydric ; with sulphur, sulphydric acid ; 
with nitrogen, ammonia ; and with cyanogen, cyanhydric, or 
Prussic acid. 

Q. For what does hydrogen display a strong affinity ? 

A. Caloric. So that it cannot, per se, be separated from it. 

Q. What advantage has been taken of the levity of this gas ? 

A. The. formation of balloons. Its specific gravity is .0694. 

Q. Can water be obtained by artificial means ? 

A. Yes. It is produced by the combustion of oxygen gas 
with Ijydrogen gas? 

Q. What are the properties and uses of water? 

A, It is very important as a solvent, and is essential to some 
crystals and to galvanic processes. Water unites with earths 
and alkalies, producing heat during combination with them, 
which results in compounds called hydrates. 

Q. Is there air in water ? 

A. Yes. Fishes cannot live in water which, either by boil- 
ing or exhaustion, is deprived of air. 

Q. What is the composition of water ? 

A. It consists of one atom of hydrogen to one atom of oxygen, 
or, in volumes, of 1 volume of hydrogen to half a volume of 
oxygen; equivalent number 9. 

Q. Does hydrogen or oxygen combine in any other propor- 
tion ? 

A. Yes. So as to form deutoxide of hydrogen. 

Gl. How procured ? 

A. By dissolving deutoxide of barium in muriatic acid liquid* 
precipitating the barytes by sulphuric acid and the chlorine by 
silver. 

Q. What are the peculiar properties of deutoxide of hydro- 
gen ? 



44 CATECHISM ON CHEMISTRY. 

A. It is a colourless liquid — nearly inodorous metallic taste 
— produces a smarting sensation on the skin — more difficult to 
vapourize than water, and gives off oxygen explosively with 
some substances, such as silver, gold, (fee. 

Q. What happens if hydrogen and chlorine be mixed together 
in equal volumes ? 

A. They combine spontaneously, and form chlorohydric acid, 
(muriatic acid). 

Q. Does the light influence this union ? 

A. Yes. For in the dark it takes place slowly, but in the 
solar rays explosively. 

CHLOROHYDRIC, OR MURIATIC ACID GAS. 

Q. How is chlorohydric acid procured ? 

A. By the action of sulphuric acid on chloride of sodium 
with heat. The water of the sulphuric acid is decomposed ; its 
oxygen unites with the sodium, forming soda, with which the 
sulphuric acid combines, forming sulphate of soda. The hy- 
drogen of the water, and the chlorine, escapes as muriatic acid. 

Q. What are the properties of muriatic acid ? 

A. It is a colourless gas, irrespirable, does not support com- 
bustion, very absorbable by water, decomposed by the alkaline 
metalloids, and produces white fumes if allowed to escape into 
the air, in consequence of combining with moisture, for which 
it has a remarkable affinity. 

Q. What is the composition of this gas ? 

A. One atom of hydrogen to one atom of chlorine, or one 
volume of each resulting in two volumes. Equivalent number 
is 37. 

Q. How is liquid chlorohydric acid obtained ? 

A. By saturating water with the gas in Woulfe's apparatus. 

Q. What are the properties of liquid muriatic or chlorohydric 
acid ? 

A. When pure, colourless ; generally straw-coloured, from 



CxVTECHISM ON CHEMISTRY. 45 

containing a minute portion of iron. It unites with those alka- 
lies, earths, and oxides only, which form with it soluble salts. 

Q. What effect has heat and desiccation on its combinations? 

A. It converts them into chlorides. Muriates of magnesia 
and alumina are exceptions. 

Q. Is there a chloride of ammpnia ? 

A. No. Chlorine decomposes it by its affinity for hydrogen. 
*Q,. What was the old theory of muriatic acid ? 

A. It was deemed a compound of oxygen with some un- 
known radical. When distilled with red oxide of lead, or per- 
oxide of manganese, oxygen was supposed to combine with it, 
forming oxygenated muriatic acid, the name then given to 
chlorine. 

Gl. How did they account for the activity of chlorine as a 
supporter of combustion ? 

A. To the oxygen imagined to exist in it. 

Q. What did really happen in all those processes in which 
muriatic acid was thought to receive oxygen ? 

A. It was deprived of hydrogen. 

Q. How is it proved that oxygen is not a constituent of chlo- 
rine ? 

A. Charcoal, even when ignited by the voltaic pile, is not 
acted upon by dry chlorine, nor are metals oxidized thereby. 

Gt. How may idohydric acid be procured. 

A. By transmitting hydrogen and vapour of iodine through 
a red hot tube. Or by the action of water on iodide of phos- 
phorus, the former being decomposed, the oxygen unites with 
phosphorus to form phosphoric acid, and the hydrogen with 
iodine forming idohydric acid, which passes over. 

Q. What are the properties of this substance? 

A. It is a gas possessing acid properties, produces dense 
white fumes with the air, and has an odour not unlike muriatic 
acid gas. It is very absorbable by water, and combines with 
alkalies forming idohydrates. 

Q,. How is bromohydric acid procured ? 



46 CATECHISM ON CHEMISTRY. 

A. By mixing the vapour of bromine with sulphuretted hy- 
drogen. 

Q. What are the compounds of hydrogen with sulphur? 

A. Sulphydric acid (sulphuretted hydrogen) and the polysul- 
phide of hydrogen. 

SULPHYDRIC ACID. 

Q. How is sulphdyric acid obtained ? 

A. By the action of diluted sulphuric acid on a sulphide. 
Sulphide of iron is mostly employed in a contrivance called 
the self-regulating reservoir. Water is decomposed, the oxygen 
uniting with iron, with which the sulphuric acid combines, 
while the hydrogen, with the sulphur, escapes as sulphydric 
acid. It is also found native in some mineral waters, and is 
evolved from privies. 

Q. What are the properties of sulphuretted hydrogen? 

A. It is a gas, with the odour of rotten eggs, irrespirable, 
does not support combustion, inflammable, burning with a pale 
blue flame, and absorbable by water. 

Q. For what class of substances is sulphydric acid a test ? 

A. The metals forming with them sulphides. All metallic 
solutions, however, are not decomposed by this acid, of which 
iron, nickel, cobalt, manganese, titanium, and molybdenum 
furnish examples. 

Q. What is the best test for sulphydric acid ? 

A. Lead, forming a black sulphide. 

Q. WLat is the composition of this gas? 

A. Sulphur and hydrogen, each one atom. 

Q. What does hydrogen form with selenium and tellurium ? 

A. With the former selenhydric acid, commonly called sele- 
nuretled hydrogen ; with the latter, telluhydric acid, known as 
telluretted hydrogen. 



CATECHISM ON CHEMISTRY. 47 



NITROGEN. 



Q. In what does nitrogen exist ? 

A. In the atmosphere, forming four-fifths of its bulk. Its 
ponderable base is a principal element in animal matter. 

d. How is nitrogen procured ? 

A. By the decomposition of the atmosphere with any sub- 
stance which will, in a close vessel, abstract oxygen from the 
included portion of air; as, for instance, by the combustion ot 
phosphorus, or by iron filings, and sulphur moistened. 

Q,. What are the properties of nitrogen ? 

A. It is a gas, distinguished by a comparative want of pro* 
perties. It does not support life nor combustion. Its most 
distinguished property is its strong affinity for caloric, so as to 
carry it into combination with it. Its equivalent number is 
14; specific gravity, 0.9722. 

Q. In what peculiar substances is nitrogen an ingredient ? 

A, A majority of the most fulminating compounds. 

Q. Is the air a compound or mixture ? 

A. It is a mixture, having no properties of a compound ? 

GL. What is the composition of the air ? 

A. Composed of nitrogen near four-fifths; oxygen near one- 
fifth, a little carbonic acid, aqueous vapour, and near the sea 
supposed to be a little muriatic acid. 

Q. What is that science called, the object of which is the 
analysis of the air ? 

A. Eudiometry. Hydrogen is generally employed as a cudi- 
melrical substance or agent, which, on being subjected to the 
electric spark, unites with the oxygen to form water. 

Q. Can you give the process of analyzing the air? 

A. Take a given quantity of air, and add enough hydrogen 
to convert all the oxygen present into water. The oxygen and 
hydrogen having disappeared, form the deficit, which, being 



48 CATECHISM OX CHEMISTRY. 

divided by three, will give the quantity of oxygen present in 
the given number of measures of the atmosphere. 

Q.. What is the composition of the atmosphere in atoms and 
in volumes ? 

A. Composed of two atoms of nitrogen to one of oxygen ; and 
in volumes, two of nitrogen to half a volume of oxygen, which 
results (being no condensation) in two and a half volumes. 
Equivalent, 36. 

COMPOUNDS OF NITROGEN AND OXYGEN. 

Ct. What are the compounds of nitrogen and oxygen? 

A. There are five compounds; namely, nitrous oxide, nitric 
oxide, hyponitrous acid, nitrous acid, and nitric acid. 

Q. How is nitrous oxide procured ? 

A. By the action of dilute nitric acid on zinc, or by exposing 
nitric oxide to iron filings. The best mode is to subject nitrate 
of ammonia to destructive distillation. Three equivalents of 
oxygen from the nitric acid, with three equivalents of hydrogen 
of the ammonia, form water, while the two equivalents of nitro- 
gen which are left from the ammonia and nitric acid, unite with 
the remaining two equivalents of oxygen to form two equiva- 
lents of nitrous oxide. Hence the residue is water and nitrous 
oxide. 

Q,. What are the properties of nitrous oxide ? 

A. It is an invisible gas, supports combustion, rendered 
liquid by great pressure, absorbed by water, and when respired 
productive of a peculiar transient inebriety. 

Q. What is the composition of nitrous oxide ? 

A. Nitrogen and oxygen each one atom ; in volumes,, one of 
nitrogen to half a volume of oxygen. Its proper name is pro- 
toxide of nitrogen. 

Q,. How is nitric oxide procured ? 

A. By the reaction of nitric acid on copper, silver, or other 
metals, by means of the self-regulating reservoir. 



CATEOHISM ON CHEMISTRY. 49 

Q. What are the properties of nitric oxide, or deutoxide of 
nitrogen ? 

A. It is an invisible gas, slightly absorbed by water, sup- 
ports the combustion of some combustibles, but extinguishes a 
candle flame; irrespirable, explodes with ammonia, and on ac- 
count of its distinguishing property of combining with the oxy- 
gen of the air, forming red fumes, it is impossible that it should 
exist where the atmosphere has access. 

Q.. What does it form by union with the atmosphere ? 

A. Nitrous acid red fumes. 

Q,. What is the composition of nitric oxide? 

A. It consists of one atom of nitrogen to two atoms of oxy- 
gen, and one volume of each resulting in two volumes of ^ieut- 
oxide of nitrogen, without condensation. 

GL. How is nitrous acid formed ? 

A. By mixing two volumes of deutoxide of nitrogen with 
one volume of oxygen ? 

Q.. What are the properties of nitrous acid ? 

A. It is a gas, of a green orange colour, irrespirable, and 
supports combustion ? 

Q,. To what scientific purpose has nitric oxide been appro- 
priated ? 

A. As a eudimetrical substance. 

Gt. How do you explain the analysis of the air by nitric 
oxide ? 

A. Nitric oxide, uniting with oxygen, forms nitrous acid, 
which, being absorbed, forms the deficit. As nitrous acid con- 
sists of three volumes, one of oxygen and two of deutoxide of 
nitrogen, dividing the deficit by three will give the quantity of 
oxygen in the given measures of the air. 

Q.. What is the atomic composition of nitrous acid ? 

A. One atom of nitrogen to four of oxygen. 

Q.. What is the composition of hyponitrous acid ? 

A. One atom of nitrogen to three of oxygen ; in volumes, 
one of nitrogen to one and a half of oxygen. 
5 




50 CATECHISM ON CHEMISTRY. 

NITRIC ACID (AaUA FORTIS.) 

Gt. How is nitric acid usually procured ? 

A. By the action of sulphuric acid on nitre aided by heat. 
The nitric acid is displaced by the superior affinity of the sul- 
phuric acid for the potash, and being vapourized by the heat, 
passes into the receiver, where it condenses into a liquid. 

Gt. What are the properties of nitric acid 7 

A. When pure, it is a colourless liquid, though usually 
orange coloured, it destroys organic matter, reacts powerfully 
on metals, and ignites oil of turpentine, charcoal and phos- 
phorus. Nitric acid forms the base of some of the most ful- 
minating compounds. 

Q,. What is nitroso-nitric acid ? 

A. It is an orange coloured fuming liquid, consisting of a 
mixture of nitric acid and nitric oxide. 

Gl. How is it obtained ? 

A. It results from a deficiency of water during the process of 
obtaining nitric acid. 

Gt. What properties characterize this ? 

A. It is more energetic than nitric acid in its reaction with 
inflammable substances, it ignites the essential oils and carbon, 
and explodes with phosphorus, and by exposure to heat, is con- 
verted into pure nitric acid by giving up nitrous acid. 

Q. What is gunpowder ? 

A. A mixture of nitre, charcoal and sulphur. 

Gl. What is the composition of nitric acid ? 

A. It consists of nitrogen one atom to oxygen five atoms. 

Gt. How is nitric acid tested ? 

A. By its power of dissolving gold leaf, when mixed with 
muriatic acid. 

CI. Does nitrogen combine with chlorine and iodine ? 

A. Yes. There are a chloride and iodide of nitrogen. 

Gt. How is the chloride of nitrogen obtained ? 



CATECHISM ON CHEMISTRY. 51 

A. By placing a bell glass filled with chlorine over a solu- 
tion of nitrate of ammonia, the chloride appears in oleaginous 
drops, which subside at the bottom of the basin. 

Q,. How is the iodide of nitrogen obtained ? 

A. By putting iodine into a solution of ammonia. The 
alkali is decomposed with formation of idohydric acid and 
chloride of nitrogen, the latter subsiding in the form of a dark 
powder. 

Q,. What are the striking properties of the chloride and 
iodide of nitrogen ? 

A. Their very explosive nature. 

COMBUSTION. 

Gl. What is combustion ? 

A. A state of intense chemical action, accompanied with an 
evolution of heat and light. 

Gt. What was Stahl's theory of combustion ? 

A, That all substances in burning give out a common prin- 
ciple of inflammabilityj called phlogiston. 

Ct. Was the Stahlian doctrine objectionable ? 

A. It was, because metals become heavier during combus- 
tion. By the advocates of this doctrine, a metallic oxide was 
considered as a simple substance, and the metal itself was 
deemed a compound of its oxide with phlogiston. Carbon was 
regarded by them as phlogiston nearly pure, and that on burn- 
ing, it became phlogisticated air, the name then given to ni- 
trogen. 

Q,. What effect had the discovery of oxygen on the phlogistic 
theory ? 

A. It proved fatal to it, because its absorption in combustion 
is the reason that metals become heavier, 

Q. Who had the honour of establishing the antiphlogistic 
theory ? 

A. Lavoisier : who found that combustion and oxidation in 



52 CATECHISM ON CHEMISTRY. 

general, consist in the combination of the combustible matter 
with oxygen. On burning phosphorus in a jar of oxygen, he 
found that a quantity of the gas disappeared, that the phos- 
phorus gained weight, and that the increase of the latter ex- 
actly corresponded to the loss of the former. 

Q. Did Lavoisier entertain entirely correct views on the 
subject ? 

A. No. He made combustion to consist in the union of 
oxygen with combustible bodies solely, not providing for ex- 
ceptions, as when metals enter into combustion v/ith chlorine 
or sulphur. 

Q,. To what does the heat and light of combustion appear to 
be due ? 

A. The former to the agent, or supporter, the latter to the 
combustible. 

Q,. What is the product of the combustion of a combustible 
body in oxygen gas ? 

A. Either an ordinary oxide, an acid, or an alkali. 

d. What nomenclature is given to oxides expressive of the 
degree of oxidizement? 

A. A compound of the combustible with one atom of oxygen 
is called protoxide; with two atoms of oxygen, deutoxide ; 
with three, tritoxide ; and the higliest degree of oxidizement is 
denominated peroxide. 

QL. What results from burning metals in chlorine, iodine, 
bromine, &c. ? 

A. Chlorides, iodides, and bromides. The nomenclature of 
these does not vary from oxides. 

ACIDITY. 

Q,. What properties distinguish acids? 
A. They have a sour taste, redden vegetable blues, and re- 
store colours changed by alkalies, and generally are very 



CATECHISM ON CHEMISTRY. 53 

soluble, and capable of uniting in definite proportion with 
alkaline bases. 

Gl. Are all acids sour ? 

A. Silex being insoluble does not taste sour. 

Q. Do all acids redden vegetable blues ? 

A. No. Sulphurous acid whitens litmus, and indigo is not 
reddened by any acid. 

Q. Is oxygen the sole acidifying principle? 

A. It is not. Chlorohydric, sulphydric, and cyanhydric, 
(prussic acid,) are acids containing no oxygen. 

Q. What is the nomenclature expressive of the quantity of 
oxygen or other acidifying agent in an acid ? 

A. The name of that acid which contains the most oxygen 
is made to terminate in ic, and that which contains the lesser 
in ous ; thus we have sulphuric and sulphurous acids. When 
the acidifying radical is capable of forming acids with more 
than two proportions of oxygen, that acid which contains less 
oxygen than the one ending in oms, is distinguished by having 
hypo prefixed. This word is also applied when the acid con- 
tains more oxygen than one ending in oms, but less than that 
of one ending in ic. An example of the former is furnished by 
hypo-sulphurous acid, and of the latter by hypo-sulphuric acid. 

d. What vegetable substance is generally used for testing 
acids ? 

A. Litmus, which is changed from blue to red by them. 

Q., Is there any body to which the term acidifying principle 
is strict)" applicable ? 

A. There is not. As oxygen, in combining with substances 
forms alkalies as well as acids ; it may be deemed a new pro- 
perty peculiar to the compound. 

ALKALINITY. 

Gl. What properties distinguish alkalies ? 

A. Their peculiar alkaline taslc, by producing in certain 

5* 



54 CATECHISM ON CHEMISTRY. 

vegetable substances peculiar changes, neutralizing acids, and 
restoring colours changed by them ; and combining with oils, 
rendering them soluble in water. 

Q.. Will all alkalies render oils soluble ? 

A. Some of the alkaline earths do not. 

Q.. What vegetable substance is the best test for alkalies ? 

A. A blue infusion obtained from red cabbage; which is 
rendered green by any alkali. 

Gl. Are all the alkaline bases metallic oxides? 

A. Excepting ammonia and the vegetable alkalies, they are 
all oxides of metals. 

AMMONIA. 

Q,. In what does ammonia exist? 

A. Excepting the alkaline vegetables, with a few others, its 
existence is exclusively in animal matter. 

Ct. What is ammonia ? 

A. It is a gaseous compound, of one equivalent of nitrogen to 
three of hydrogen. 

Q,. How is ammonia procured ? 

A. By heating together slacked lime and muriate of ammo- 
nia. The muriatic acid unites with the lime, and the ammonia 
escapes. 

Gl, What are the properties of ammonia? 

A. It is a colourless gas, irrespirable, not inflammable in 
air, yet explodes with chlorine, in consequence of th^ffinity of 
the latter for hydrogen, and is very absorbable by water. In 
consequence of its pow^erful alkaline properties, and volatile 
nature, it is called the volatile alkali. 

CI. How is liquid ammonia obtained ? 

A. By passing the gas into water, 

Q.. What are the properties of liquid ammonia? 

A. It is a colourless liquid, of a caustic acrid taste, and pecu- 
liar pungent smell. When concentrated it blisters the tongue 



CATECHISM ON CHEMISTRY. 55 

and skin, boils at 150°, is very attractive for carbonic acid, and 
capable of dissolving resins and many vegetable substances. It 
is incompatible with all acids, and most of the earthy and me- 
tallic salts. The best antidote for the poisonous effects of am- 
monia is vinegar, which forms with it the acetate of ammonia. 

Gl. What are some of the salts of ammonia ? 

A. The sulphate, muriate, and carbonates. The carbonate is 
generally known as the salt of ammonia. 

Q. What is the old name for ammonia ? 

A. Hartshorn, derived from the circumstance of obtaining it 
from the horn of the hart. 

Q. How is the muriate of ammonia obtained ? 

A. By the destructive distillation of animal matter we obtain 
ammonia, water, carbonic acid, and empyreumatic oil, which 
results in impure subcarbonate of ammonia, water, &c. Then 
by the double decomposition between common salt and the 
sulphate of ammonia, which is formed by saturating the pro- 
ducts with sulphuric acid, muriate of ammonia and sulphate of 
soda are obtained. 

Q,. How is the common carbonate procured ? 

A. By heating a mixture of muriate of ammonia and car- 
bonate of lime. It is a subcarbonate. 

Gl. What effect has the air on this salt if exposed for a time 
to it? 

A. Ammonia is volatilized in a sufficient quantify to convert 
it into a bicarbonate. 

Gt. What is the composition of ammonia in volumes ? 

A. Of one volume of nitrogen to three of hydrogen, resulting 
in four volumes, which are condensed into two. 

Q,. Can ammonia be resolved into a metallic base ? ; 

A. Some chemists have inferred the existence of such a 
principle, called ammonium. , 



56 CATECHISM ON CHEMISTRY, 



PHOSPHORUS. 



CI. From what may phosphorus be obtained ? 

A. Phosphate of lime in bones, or phosphate of soda in urine. 

Q,. How is it procured ? 

A. By subjecting bones to heat, in order to destroy the ani- 
mal matter existing in them, we have left phosphate of lime. 
The phosphate of lime thus obtained is decomposed by the ac- 
tion of sulphuric acid into sulphate of lime, and superphosphate 
of lime. On the addition of boiling water, the superphosphate 
is dissolved, and may be separated by filtration : evaporate this 
to the consistence of a syrup, and then ignite it in a retort with 
charcoal, the beak of which is allowed to enter some water. 
The phosphorus distils into the water in tears. From phos- 
phate of soda phosphorus may be obtained by complex affinity 
with nitrate of lead. Phosphate of lead is formed, which 
yields phosphorus by distillation with charcoal. 

CI, What are the properties of phosphorus ? 
. A. It is a flexible, colourless, or flesh coloured, translucent 
solid, susceptible of a slow and quick combustion; inflames at 
the temperature of 119°, boils at 550°, of the odour of garlic, 
insipid, and insoluble in water. Equivalent number 12. 

Gl. What are the compounds of phosphorus and oxygen ? 

B. An oxide of phosphorus, phosphoric, phosphorous, and 
hypophosphorous acids. 

Cl. What is the composition of this oxide? 

A. Three atoms of phosphorus with one of oxygen. 

Q,. What is the composition of hypophosphorous acid ? 

A, Two atoms of phosphorus with one atom of oxygen. 

Q. How is phosphorous acid obtained ? 

A. By passing vapourlzed phosphorus over corrosive subli- 
mate heated in a tube, chloride of phosphorus results, which, 
by the decomposition of water, forms muriatic and phosphorous 



CATECHISM ON CHEMISTRY. 51 

acids. The former, being most volatile, may be separated by 
heat. 

Gt. What are the properties of phosphorous acid ? 

A. It is a colourless solid, strong taste and smell, and sus- 
ceptible of volatilization. 

Gt. What is the composition of this substance? 

A. Two atoms of phosphorus with three atoms of oxygen. 

QL, How is phosphoric acid obtained ? 

A. By the ordinary combustion of phosphorus in the air, or 
oxygen, or by the decomposition of bones. Commonly pro- 
cured by adding phosphorus gradually to nitric. acid heated. 

Gl. What are the properties of phosphoric aqid ? 

A. It is a solid, unalterable by heat, strong taste, inodorous, 
and soluble in water. 

Q. What is the composition of phosphoric acid ? 

A. Two atoms of phosphorus with five atoms of oxygen. 

Gl. What is formed when this acid is exposed to a red heat, 
and afterwards cooled ? 

A. Paraphosphoric acid, which is a transparent, brittle glass. 
Nitrate of silver yields with phosphoric acid a yellow precipi- 
tate ; with paraphosphoric acid a white one. 

Gl. What is the acid contained in fused phosphate of soda 
considered to be? 

A. A third species, called pyrophosphoric acid. These all 
agree in composition, but not in properties, and hence they are 
termed isomeric bodies. 

Gl. With what other substances does phosphorus combine ? 

A. With chlorine, bromine, iodine, sulphur, selenium and 
hydrogen. 

Gl. What is formed by phosphorus with hydrogen ? 

A. Protophosphoretted hydrogen and perphosphoretted hy- 
drogen. 

Gl. How is protophosphoretted hydrogen obtained ? 

A. By adding some phosphorus to the materials for gene- 
rating hydrogen. Or, after filling a small retort with a solution 



58 CATECHISM ON CHEMISTRY. 

of caustic potash, displace about two-thirds of the solution. by 
introducing hydrogen gas. Then introduce a given quantity 
of phosphorus, and apply heat. Water is decomposed by the 
alkah, and phosphate of potash is formed by the union of 
phosphorus, oxygen and potash. The hydrogen of the water 
dissolves a portion of the phosphorus, which is spontaneously 
inflammable, so that it explodes as it escapes, and forms a 
succession of beautiful rings of smoke. Protophosphoretted 
hydrogen may also be obtained by the action of phosphide of 
lime on water. 

Q,. What are the properties of this substance? 

A. It is an inflammable gas, with a garlic smell, and on 
meeting with oxygen, becomes luminous in the dark. 

d. What is the composition of this gas ? 

A. It consists of phosphorus and oxygen, each one atom. 

Q,. How is perphosphoretted hydrogen obtained ? 

A. By heating, in a retort, phosphorus, slacked lime and 
water. 

d. What are the properties of perphosphoretted hydrogen ? 

A. It is a colourless gas, with a gariic smell, bitter taste, and 
smokes when exposed in the air. 

CARBON. 

d. What is a specimen of pure carbon? 

A. The diamond. 

(X. In what is carbon found to exist? 

A. The various kinds of coal, as the anthracite and bitumi- 
nous coal, as an essential element in animal and vegetable mat- 
ter, and is especially a constituent of the fibres of wood. 

Q. How is it obtained? 

A. By burning wood with a smothered flame, in a limited 
access of air. The heat drives off all the oxygen and hydro- 
gen, and nothing is left but charcoal. 

Q,. Can you give the properties of carbon ? 



CATECHISM ON CHEMISTRY. 59 

A. Charcoal is black, insipid, inodorous, next lo metals the 
best conductor of electricity, one of the best radiators and worst 
conductors of heat, and absorbs moisture. 

Q. To what cause is attributed its non-conducting" power ? 

A. Its porosity, as in the form of anthracite ; carbon con- 
ducts heat better. 

Q,. What is the hardest and most brittle substance known ? 

A. Crystallized carbon, or diamond. 

Q,. How is the identity of carbon and the diamond proved? 

A. When equal weights of charcoal and diamond are 'seve- 
rally exposed to the rays of a powerful lens, in oxygen gas 
included in different bell glasses, they are both converted into 
carbonic acid. The equivalent weight of carbon is represented 
by 6. 

QL- Is charcoal used in the arts ? 

A. Yes. It is used as a disinfecting agent, in preserving 
meat, in purifying water, and in consequence of its affinity for 
colouring matters, it is extensively used in refining sugar. 

Gl. With what does carbon combine ? 

A. Oxygen, hydrogen, nitrogen, sulphur and chlorine. 

Gl. Can you enumerate the compounds of oxygen and car- 
bon ? 

A. Carbonic oxide, carbonous, and carbonic acid. 

d. How is carbonic oxide procured ? 

A. By heating chalk with iron filings in a gun barrel at a 
white heat. The carbonic acid of the carbonate is liberated, 
part of the oxygen of which is detained by the iron. 

Ct. What are the properties of carbonic oxide ? 

A. It is a deleterious gas, irrespirable, and does not support 
combustion. 

Gl. What is its composition ? 

A. Carbon and oxygen, each one atom. 



60 CATECHISM ON CHEMISTRY. 



CARBONIC ACID. 

Q,. Where does carbonic acid exist ? 

A. In the atmosphere in a very small proportion, and is a 
product of combustion and of the respiration of animals. It is 
a principal ingredient in marble and limestone, existing in the 
state of carbonate. 

Gl. How is carbonic acid procured ? 

A. By the action of an acid, or heat, on any carbonate. 
Usually by the superior affinity of sulphuric acid for the lime 
in marble. It is also produced by the combustion of charcoal, 
and is evolved during the vinous fermentation. 

Q,. What are the properties of carbonic acid? 

A. It is a colourless gas, rendered liquid by great pres- 
sure. 

solidified at 148® below zero, irrespirable, extinguishes flame, 
and absorbable by an equal bulk of water. It is a heavy gas, 
specific gravity being 1.52. 

Gl. What does it form insoluble compounds with ? 

A. Lime, barytes, and oxide of lead; consequently these form 
good tests for it. 

Q. Does it possess good medical qualities ? 

A. Yes. It is antiseptic, and in water grateful to the sto- 
mach. 

Gl. What is the common mineral water of the shops ? 

A. Water impregnated with carbonic acid. 

Gl. What is considered the best test for carbonic acid? 

A. Lime ; on the water of which it forms a pellicle of car- 
bonate of lime. 

Gl. What is the composition of carbonic acid? 

A. One atom of carbon to two atoms of oxygen. 

Gl. What are some of the peculiarities of solid carbonic acid? 

A. It is perfectly white, of a spongy texture, evaporates 



CATECHISM ON CHEMISTRY. 61 

rapidly, producing cold; it is capable of producing the most in- 
tense cold, and when held against a living animal surface, it 
blisters and destroys the vitality of the part. 

OXALIC ACID. 

Q. What is oxalic, or carbonous acid ? 

A. It is a vegetable acid, in the state of a crystalline solid 
possessing poisonous properties. 

Q,. What is its composition ? 

A. It consists of carbonic oxide with carbonic acid, each one 
atom, with water. Its solid state is owing to the water which 
enters into its composition. 

Gt. How is this composition proved ? 

A. By the affinity of sulphuric acid for water, the two gases 
may be separated. With lime water, the carbonate acid may 
be removed from the carbonic oxide. 

Gt. How is oxalic acid obtained? 

A. By the action of nitric acid on sugar. It may also be 
procured from starch, molasses, common sorrel, wood sorrel, 
&c. 

Gl. From what does it derive its name ? 

A. Oxalis acetosellaj in which it exists in the state of bin- 
oxalate of potash. 

Gt. Give the properties of oxalic acid ? 

A. It is a solid, having a sour taste, soluble in water and 
alcohol — with chlorohydric acid forms a crystalline compound, 
called chloroxalic acid, and it is an energetic poison. 

Gt. What is the best antidote ? 

A. Magnesia and chalk. 

Q,. What are other compounds of carbon with oxygen? 

A. Mellitic and croconic acids. 

Gt. What is the best test for oxalic acid ? 

A. Lime, with which it forms an insoluble oxolate, 
6 



62 CATECHISM ON CHEMISTRY. 

Q,. What is the ultimate composition of oxalic acid? 

A. Two atoms of oxygen with three atoms of carbon. 

Gl. What is formed by the union of carbon with hydro- 
gen? 

A. Light carburetted hydrogen (fire damp) and deutocarbo- 
hydrogen, or defiant gas. 

Q.. Enumerate the two groups of compounds of carbon with 
hydrogen ? 

A. In the first there are four, viz: light carburetted hydro- 
gen, carbohydrogen, bicarburet of hydrogen and naphthaline. 
In the second there are five, namely, protocarbohydrogen, deu- 
tocarbohydrogen, tritocarbohydrogen,tetartocarbohydrogen and 
hexacarbohydrogen. 

Gl. By what names is light carburetted hydrogen distin- 
guished ? 

A. Inflammable air, carburetted hydrogen (fire damp) and 
bihydroguret of carbon. 

Gl. How is it procured? 

A. From the mud of stagnant water, from which it is libe- 
rated, and collected by means of inverted bottles. 

Gl. What are the properties and composition of this gas? 

A. It is colourless, irrespirable, and having more than a 
negative influence in destroying life. Composed of two volumes 
or atoms of hydrogen, with one volume or atom of carbon, con- 
densed into one volume. 

Gl. How is defiant gas or deuto-carbohydrogen obtained ? 

A. By distilling alcohol with sulphuric acid. The acid unites 
with the water of the alcohol, and leaves the gas. 

Gl. Give the properties and composition of this gas ? 

A. It is invisible, elastic, when inhaled produces asphyxia, 
burns with splendour, and detonates violently with oxygen. 
Composed of carbon vapour and hydrogen, each one atom, and 
in volumes, one of each condensed into half a volume. 

Q. What is a solid compound of hydrogen and carbon ? 



CATECHISM ON CHEMISTRY. 63 

A. A crystalline substance obtained by the distillation of 
tar from the neck of the retort where it crystallizes. It is called 
naphthaline, has an aromatic smell, and a pungent, disagreeable 
taste. 

Gl. From what substances in general may the compounds 
of carbon and hydrogen be obtained 1 

A. By the distillation of bituminous coal, wood, oil, tar, and 
other inflammable substances. 

Gt. What general properties distinguish these compounds? 

A. Tlieir inflammability and volatility. They do not sup- 
port combustion, and in the vaporous or liquid form are highly 
stimulating. In the gaseous state they constitute the flame of 
candles, lamps, gas lights and culinary fires. 

Q,. On what depends the illuminating power of these gases? 

A. The proportion or quantity of carbon condensed into a 
volume, provided there be enough oxj'gen to consume it. If 
carbon be in excess the flame is rendered smoky. 

CYANOGEN. 

Gt. What is the most expressive name for cyanogen ? 

A. Bicarburet of nitrogen. 

Q,. How is cyanogen obtained ? 

A. By distilling the bi-cyanide of mercury. 

Gl. What are the properties of cyanogen? 

A» It is a gas, irrespirable, colourless, rendered liquid by 
pressure, absorbable by water, and still more by alcohol ; and 
is characterized by burning with a beautiful violet flame. In 
relation to the galvanic poles, it is electro-negative. 

Gl. What happens when it is detonated with a quantity of 
oxygen ? 

A. It is converted into two volumes of carbonic acid and 
one of nitrogen. 

Gl. What is the composition of cyanogen ? 



64 CATECHISM ON CHEMISTRY. 

A. It consists of two volumes of carbon vapour and one of 
nitrogen, condensed into one volume. 

Q,. What does cyanogen form with hydrogen ? 

A. Cyanhydric or prussic acid. 

CI. How is prussic acid procured ? 

A. By the distillation of bi-cyanide of mercury with muri- 
atic acid. The acid is decomposed, the chlorine unites with 
the mercury, forming bi-chloride, and the hydrogen and cyano- 
gen pass over as prussic acid. 

CI. How is prussic acid made of sufficient strength for 
medical purposes? 

A. Add one pound of muriatic acid, diluted with six pints 
of water, to a pound of the bi-cyanide ; after which bring over 
six pints. Another mode of obtaining the strongest cyan- 
hydric acid, is by exposing crystals of bi-cyanide of mercury 
in a tube to sulphuretted hydrogen, and condense the vapours in 
a receiver surrounded by salt and snow. 

Gt. What are the properties of cyanhydric or prussic acid ? 

A. It is a colourless liquid, the most volatile substance 
known; freezing by its own evaporation; of a cooling taste, 
and is deadly poisonous. 

Q. What is the composition of this acid ? 

A. It consists of cyanogen and hydrogen, each one volume 
and each one atom. 

Gt. Does cyanogen combine with any thing but hydrogen? 

A. Yes; with oxygen, forming cyanic acid ; with chlorine, 
forming chlorocyanic acid. The acid called fulminic, in ful- 
minating mercury and silver, is ascertained to be identical 
with cyanic acid. Cyanogen also unites with sulphur. 

CI. Do sulphur and carbon form a compound ? 

A. Yes; a bi-sulphide of carbon. 

Cl. How obtained ? 

A. By passing sulphur in vapour over ignited charcoal. 



CxiTECHISM ON CHExMISTRY. 65 



BORON. 

d. Where is boron ? 

A. It exists in a salt called borax. 

Q,, How is it obtained ? 

A. By the reaction of boracic acid with potassium, aided by 
heat. 

Gl. What are the properties of boron ? 

A. It is a dark olive coloured solid, insipid, inodorous, a 
non-conductor of electricity, and insoluble in water, alcohol, 
cether or the oils. It is fixed and infusible. 

d. What does it form with oxygen ? 

A. Boracic or boric acid ? 

Gt. How is boric or boracic acid procured ? 

A. By adding- sulphuric acid to a saturated solution of borax 
in water, boracic acid is precipitated in fine crystalline plates. 

Q. What is borax ? 

A. Bi-borate of soda. 



SILICON. 

Cl. In what does silicon exist ? 

A» In silex. 

d. How is silicon procured ? 

A. By heating potassium in a gas obtained by the action of 
sulphuric acid on fluoride of calcium and quartz. 

Q,. What are the properties of silicon ? 

A. It is of a dark nut brown colour, a non-conductor of 
electricity, infusible, incombustible, and soluble only in a mix- 
ture of nitric and fluoric acids. 

Gt. What is formed by the union of fluorine and silicon ? 

A. Fluo'silicic acid gas, 

Gt. What does silicon form with oxygen ? 

A. Silex or silicic acid, 

6^ 



66 CATECHISM ON CHEMISTRY. 

Q.. Where does silex exist ? 

A. It constitutes the earth of j3ints, of sand, and other stony 
matter. Rock crystal is a specimen of nearly pure silex. 

Q. How is silex procured ? 

A. By fusing powdered quartz with three times its weight 
of pearl ash, a glass is obtained, w^hich being soluble, forms 
with water a liquid called liquor of flints. By means of an 
acid silex is precipitated from this solution. 

Gl. What are the properties of silex ? 

A. It is a solid, of a white colour, insipid, inodorous, and 
unlike other acids, insoluble. It has never been volatilized. 

d. What is glass ? 

A. Silicate of potash. Prince Rupert's drops are formed by 
glass in a state effusion, being dropped into water. 

Gl. What is Derbyshire or fluor spar ? 

A. Fluoride of calcium. 

Gl. What is formed by the union of fluorine and hydrogen? 

A. Fiuohydric acid. 

Gl. How is it procured ? 

A. By the action of sulphuric acid on fluoride of calcium, in 
a leaden retort, 

Q. What are the most striking properties of fluoric acid? 

A. Its volatility, and power of corroding glass. 

Gl. What is formed when we add to the above material 
some powdered glass ? 

A. Fluosilicic acid gas, or fluoride of silicon. 

Gl. What are the striking properties of this gas? 

A. It is permanent over mercury, fumes similar to muriatic 
acid, though differing from the latter in not being so com- 
pletely absorbed by water. 

Q,. What is formed by distilling fluoride of calcium in 
powders with dry boracic acid ? 

A. Fluoride of boron, or fluo-boric acid. 

Q. What is zirconion ? 

A. A black powder, which is a non-conductor of electricity. 



CATECHISM ON CHEMISTRY. 67 

Gt. What is nilro-muriatic acid ? 

A. A mixture of nitric acid and muriatic acid. 

Q. What is the moslifetriking and useful property of this 
mixture ? 

A. That of dissolving" gold ; hence called aqua regia. 

QL. To what is its efficiency as a solvent due ? 

A. The evolution of chlorine. 

Q,. How do you explain the cause of the evolution of chlo- 
rine ? 

A. The hydrogen of the muriatic acid, and part of the oxy- 
gen unite to form water ; while chlorine, with nitrous acid, is 
evolved. 

Gt. What are the salts produced by nitro-muriatic acid ? 

A. Either chlorides or muriates. 



METALLIC RADICALS. 

Q. What properties distinguish the metals ? 

A. Their peculiar lustre when cut, and property of conduct- 
ing electricity and caloric. They are the worst radiators and 
best reflectors of heat. 

Ql. In what respect do the metals differ among themselves? 

A. In permanency of lustre, malleability, ductility, elasticity, 
tenacity, weight, and their chemical affinities. 

Q,. What metals are remarkable for their permanent lustre? 

A. Gold, silver, platinum and palladium. 

Q. What metals are most malleable? 

A. Gold, silver, copper, tin, platinum, &c. Of these, iron 
and platinum only can be advantageously hammered at high 
temperatures. 

Gl. What are the most elastic metals ? 

A. Silver, copper, but most of all iron, in the state of steel. 

Q,. What metals most ductile ? 



68 CATECHISM ON CHEMISTRY. 

A. Gold, iron, silver, copper, and, in large pipes, lead and 
tin. 

Gt. What are the magnetic metal^ 

A. Nickel, iron and cobalt. 

Gt. Which are the most tenacious ? 

A. Iron, copper and platinum. 

Q. What are the heaviest metals^ 

A. Gold, tungston, and the heaviest of all is platinum, 

Gt. Are all metals solid '? 

A. No. Mercury is a liquid at ordinary temperatures. 

Gt. With what do metals combine 1 

A. Oxygen, chlorine, iodine, bromine, ilaorlne, sulphur, phos- 
phorus, cyanogen, carbon, and with each other. 

Ql. How are metals oxidized '? 

A. Either by heat, deflagration, or the action of acids, or by 
exposure to the air with or without moisture. Thenard founded 
his division of the metals on their habitudes with oxygen. 

Gt. What metals are oxidized by mere exposure to the air 7 

A. Potassium and sodium. 

Gt. What metals require heat or moisture for oxidizement'? 

A. Iron, zinc, tin and manganese. Copper, bismuth, lead, 
nickel, antimony, arsenic, chromium, and others of this class, 
do not decompose water, either with or without heat. Mercury 
can be oxidized at a low temperature, but is incapable of de- 
composing water. 

Gt. What metals are there that cannot be oxidized either by 
heat alone or with moisture'? 

A. Gold, silver, platinum, palladium, &c. 

Q.. What are the peculiarities of metallic oxides ? 

A. Their capability of forming with acids, salts, and of 
uniting with one another. They are mostly insoluble in water, 

Gt. Do metallic oxides form the bases of every salt 1 

A. No. Salts of ammonia furnish a supposed exception to 
the rule. 

Gt. Can salts be formed by the union of metallic oxides ? 



CATECHISM ON CHEMISTRY. 69 

A. Yes. Some of them having" acid properties, form salts 
by their union with others that are alkaline. Metals are di- 
vided according as their oxides possess either of these properties 
into basefiable and acidifiable metals. The former are subdi- 
vided into those that form ordinary oxides and alkalies. 

d. What metals are alkaline ? 

A. Potassium, sodium, lithium, barium, strontium, calcium 
and magnesium. 

Q,. Can you enumerate §ome of the metals which form ordi- 
nary oxides? 

A. Iron, zinc, lead, tin, copper, 'bismuth, mercury, silver, 
gold, platinum, manganese and cobalt are the most important. 

Gl. Can you enumerate some of the acidifiable metals? 

A. Antimony, arsenic, and chromium, are the most import- 
ant. 

Ct. How are metals reduced from their oxides? 

A. Either by heat alone, or in union with combustible mat- 
ter, by the galvanic battery, and by means of deoxidizing 
agents, on metallic solutions. 

Gl, What do hydrogen and carbon form with metals ? 

A. Hydrogurets and carburets. The hydrogurets are those 
of zinc, arsenic and potassium ; and the only carburets are those 
of iron. 

Q,. What is an alloy ? 

A. It is a compound of two metals. 

Gt- What is an amalgum ? 

A. It is an alloy with mercury. 

Q. Do metals combine with each other in the solid state'? 

A. No. Attraction of cohesion, which necessarily counter- 
acts chemical affinity, must be subdued before union takes 
place. 

Gt. Do metals unite with one another in many or few pro- 
portions ? 

A. Precisely like sulphuric acid and water, when mixed to- 
gether, they combine in every proportion. 



70 CATECHISM ON CHEMISTRY. 

Ct. What is understood by the term perfect metals ? 

A. They are those which, like gold, silver and platinum, 
possess malleability, ductility, and are not tarnished by expo- 
sure to the air, nor oxidized by the heat of the forge. 

Q. What specific gravity is considered as essential for metals 
generally ? 

A. Excepting those of the alkalies and earths, they are over 
five. Consequently these are called metals proper. The term 
metalloid is applied to the metallic«radicals of the earths and 
alkalies. 

METALS OF THE EARTHS. 

Q. What are the metals of the earths proper 1 

A. Aluminium, glucinium, yttrium, and thorium. 

Q,. How can aluminium be obtained 1 

A. By the decomposition of chloride of aluminium, with 
potassium aided by heat. The chloride is made by transmit- 
ting chlorine over alumina and charcoal heated to redness. 

Q. Where is alumina, or oxide of aluminium found ? 

A. In a gem called oriental, in clay, and in alum. Also 
found as native hydrate in the form of stalactite in quartz. 

Cl. How is alumina obtained '? 

A. It is precipitated from a solution of alum by means of an 
alkali. 

Gt. What are the properties of alumina? 

A. It is white, soft, insipid, inodorous, very infusible, and 
soluble in water. 

a. What is alum? 

A. Sulphate of alumina and potash. 

Gl. Where is alum found ? 

A. It occurs native in volcanic countries, and it is largely 
manufactured in the United States from an ore which contains 
clay, sulphide of iron, sand, &c., by the aid of sulphate of 
potash. 



CATECHISM ON CHEMISTRY. 71 



ALKALINE EARTHS. 



(X' What are the metals of the alkaline earths 1 

A. Magnesium, calcium, barium, and strontium. 

Gl. How have these metals been obtained from their oxides? 

A. By galvanic means. More recently magnesium has been 
obtained by heating chloride uf magnesium with potassium. 

Gt. In what states do alkaline earths mostly occur'? 

A. As carbonates and sulphates. 

Q. What properties, as a class, do the alkaline earths possess'? 

A. They are very fixed and infusible, very sparingly soluble, 
but more so in cold than in boiling water, very attractive for 
carbonic acid, and combine with water forming hydrates. The 
alkaline earths are most soluble in water saturated with car- 
bonic acid, which accounts for their existing in nature as car- 
bonates. As a class, carbonic acid is a good test for them, 
which forms a pellicle on their solutions. 

Gt. Where is magnesia found to exist '? 

A. In sea water, and in a mineral called magnesite. 

Gt. How can it be procured 1 

A. By precipitating it from a solution of epsom salt by 
means of an alkali, in consequence of the superior affinity of 
sulphuric acid for the latter, or by depriving the carbonate of 
magnesia of carbonic acid by the aid of heat. 

Gt. What are the peculiar properties of magnesia'? 

A. Its white and friable appearance,*nearly tasteless and 
inodorous, its less energetic affinities and alkaline properties, 
its insolubility in water, and very ready solubility of its sul- 
phate. 

Gt. Where is lime found to exist ? 

A. In marble, limestone, and oyster shells in the state of 
carbonate. Lime is also found as a native sulphate, called 
plaster of Paris. 

Gt. How is lime obtained ? 



72 CATECHISM ON CHEMISTRY. 

A. By expelling water and carbonic acid fronfi limestone by 
heat. 

Q. What are the disting-uishing properties of lime'? 

A. It is of a light gray colour, of an acrid, caustic taste, 
absorbs water and carbonic acid from the air, becoming white ; 
with the former it becomes a hydrate, and it is slightly soluble. 

Q,. What phenomenon attends the slacking of lime ? 

A. The caloric which exists in the water, as the cause of its 
fluidity, is evolved. 

Q,- How much lime will water hold in solution 7 

A. About one-seven hundredths of its weight, forming lime 
water, 

Q.. What forms a pellicle on lime water when exposed to the 
air'? 

A. Carbonate of lime, which results from the affinity of the 
carbonic acid of the air for the lime. 

Q. What is the best test for lime'? 

A. Oxalic acid, forming an insoluble oxalate of lime. 

Gl. What is the chemical name for lime *? 

A. Protoxide of calcium. 

Gt. What is baryta or barytes '? 

A. The oxide of barium. 

Gl. How is baryta obtained 1 

A. By dissolving the native carbonate in nitric acid, filtering 
the solution, evaporating, and then, by heat, driving off the 
acid. 

Q. What are the properties of baryta ? 

A. It is of a dark gray colour, absorbs water, and becomes 
light, like lime in its properties, but more acrid and caustic, 
and is a poison. It is distinguished from other alkaline earths 
by the insolubility of its sulphate and superior weight. Its 
specific gravity is 4. 

Q,, What is the best test for baryta ? 

A. Sulphuric acid, which forms the insoluble sulphate. 

Gl. How is strontia or protoxide of strontium obtained'? 



CATECHISM ON CHEMISTRY. 73 

A. From its carbonate or sulphate exactly as baryta is from 
its carbonate. 

Q,. What properties distinguish it from barytas 1 

A. By its being less soluble, but more so in boiling than 
cold water, its crystallization, and not being poisonous. 

a. What is the test 1 

A. The red colour, which its solutions give to flame. 

METALS OF THE PROPER ALKALIES. 

Q. What are the metals of the alkalies proper 1 

A. Potassium, sodium and lithium. 

Gl. By whom were potassium and sodium discovered 1 

A. In the year 1807, Sir Humphrey Davy obtained them, by 
exposing their oxides, potash and soda, to the divellent influ- 
ence of the voltaic poles. Subsequently they were obtained 
hy subjecting these alkalies, in contact with iron, in a divided 
state, to intense heat in a gun barrel. More recently they 
have been reduced by heating caustic potash or soda with iron 
filings. 

Q. What are the properties of potassium *? 

A. It is white like silver, melts in the air, very attractive for 
oxygen, and takes fire on water, forming a potashuret of hydro- 
gen, which is spontaneously inflammable. The equivalent 
number of potassium is 40 and specific gravity 0.865. 

Q.. What are the peculiar properties of sodium'? 

A. Its burning on water without flame, attended with an 
effervescence and a hissing noise. It is of a bright lustre, tar- 
nishes on exposure to the air, though less rapidly than potas- 
sium. Its equivalent number is 24, and specific gravity 0.972. 

Q. What are potash and soda chemically speaking*? 

A. Oxides of potassium and sodium, 

Gl. How do they exist in nature ^ 

A. As sulphates, nitrates, and muriates, but principally in 
the state of carbonates. 
7 



74 CATECHISM ON CHEMISTRY. 

Q,, Where do the carbonates of potash and soda exist '? 

A. The former in the ashes of inland plants, the latter in 
kelp and barilla, or ashes of sea plants generally. 

Gt. What are properties common to potash (potassa) and 
soda? 

A. They are solids, of a grayish white colour, difficult effu- 
sion, caustic, and have so strong an affinity for water, with 
which they form hydrates, that they cannot exist in an atmo- 
sphere which contains moisture. In consequence of their pow- 
erful alkaline properties, they are called the fixed alkalies. 

Gt. What properties distinguish the fixed alkalies from each 
other 1 

A. Potash is the most active and deliquescent, soda efflores- 
ces ; potash is more soluble than soda, yet the salts of soda are 
more soluble than those of potash. Potash may also be dis- 
tinguished from soda, by forming a less soluble salt with tar- 
taric acid, (the bi-tartrate of potash,) and from all other sub- 
stances, by giving a yellow coloured precipitate with muriate 
of platinum, which is named chloroplatinate of potash. 

Q,. What are formed when potassium burns in the air, or 
sodium on water'? 

A. Orange coloured peroxides of these metals. 

Q,' What is caustic potash, or soda? 

A. Hydrates of these alkalies. 

Gl. How is caustic potash obtained 1 

A. By means of the double decomposition which ensues be- 
tween hydrate of lime (slacked lime) and impure carbonate of 
potash (pearl ash) when they are boiled together. Evaporate 
the solution to- dryness, and fuse it into moulds. By dissolving 
in alcohol, caustic potash thus obtained may be freed from iron 
and other impurities. 

Q. What are the important salts of potash'? 

A. The carbonates, muriate, nitrate, sulphate and tartrates. 

CI. What is the potash of commerce'? 



CATECHISM ON CHEMISTRY. 75 

A. It is a very impure carbonate, containing silex, with salts, 
and is of a variegated appearance. 

Q. How are the potashes of commerce procured '? 

A. By boihng down the ley obtained by lixiviating the ashes 
of wood or inland plants. 

Q,. How is pearlash procured 1 

A. By subjecting the potashes to intense ignition, lixiviation 
and evaporation to dryness. It is called pearlash, on account 
of its pearly white colour. 

CI. How may the purest carbonate be obtained ? 

A. By subjecting pearlash to an intense heat, triturating 
with water, and evaporating the decanted solution to dryness. 

Q.. What are some of the salts of soda'? 

A. The carbonate, sulphate, (Glauber's salt,) and muriate, 
(common salt,) and phosphate. 

Q. What are tests for soda 7 

A. The solubility of all its salts, and power of communi- 
cating to the blowpipe flame, by means of platinum wire, a rich 
yellow colour. 

Q. What alkali was discovered in 1818'? 

A. Lithia, which is found to exist in a mineral called peta- 
lite. 

d. What are the peculiar properties of lithia*? 

A. Its great neutralizing power, its forming sparingly solu- 
ble salts with carbonic and phosphoric acids, and soluble salts 
with sulphuric and oxalic acids ; and all its salts tinge the 
flame of the blowpipe red. 

d. What results from the reaction of chlorine with the me- 
tals of the earths and alkalies *? 

A. "When the oxides of calcium, barium, strontium, potas- 
sium, sodium and lithium are treated in chlorine, these metals 
are converted into chlorides, and the oxygen is expelled. 

Q. What are the properties of these chlorides 1 

A. They are generally solid, soluble in water, and, in solu- 
tion, precipitate silver, lead and black oxide of mercury. 



76 CATECHISM ON CHEMISTRY. 

Q,. What chlorides are liquids *? 

A. The bichlorides of tin and arsenic. 

Q,. Are all chlorides soluble '? 

A. No. Chloride of silver and protochloride of mercury are 
insoluble. 

Gl. What are dissolved chlorides considered to be ? 

A. Chlorohydrates or muriates. The conversion of chlorine 
into muriatic acid is effected by the decomposition of water 
which furnishes hydrogen to the chlorine. 

Q.. What muriate is decomposed by heaf? 

A. Muriate of magnesia. 

Q. How are bromides and iodides obtained '? 

A. Like chlorine, bromine and iodine unite with metallic 
substances, by displacing oxygen from their oxides. Iodine is 
capable of expelling oxygen only from potash, soda, oxides of 
lead and bismuth. 

Gl. When combined with water, what are bromides and 
iodides considered to be 1 

A. Bromohydrates and idohydrates. 

Gt. How are bromides and iodides distinguished 1 

A. Bromides emit red vapour, when heated in a tube with 
the bisulphate of potash, and do not deflagrate when thrown on 
incandescent coals. Iodides, when subjected to a small quan- 
tity of sulphuric acid in a tube, will give off a violet vapour; 
a blue colour is produced when mingled with starch, and is 
displaced from its combinations by chlorine. 

Q. What happens when potassium and sodium are heated in 
cyanogen % 

A. A cyanide is produced. Cyanide of potassium is pro- 
cured by igniting potash in contact with animal matter. Cy- 
anogen is generated by the union of carbon and nitrogen, which, 
combining with potassium, forms the cyanide. 

Gl. How are cyanides detected ? 

A. By their producing a blue colour with solutions of the 



CATECHISM ON CHEMISTRY. 77 

peroxide of iron ; also, by giving the odour of peach-blossoms 
when subjected to chlorohydric acid. 

Gt. How can sulphides (sulphurets) be formed 1 
A. Either by heating sulphur with a metal or metaM) oxide ; 
by depriving a sulphate of its oxygen, by means of heat and 
combustible matter; or by passing sulphydric acid gas into a 
metallic solution. Sulphides of lead, antimony, copper, iron, 
zinc and silver occur in nature. 

d. What properties distinguish the sulphides 1 
A. They are solid, brittle, and excepting those of the alka- 
lies and earths, are all insoluble in water. The alkaline sul- 
phides, on being moistened with water, evolve sulphydric acid, 
and still more by being subjected to chlorohydric acid. 
Gt. How distinguish selenides'? 
A. When heated they produce the smell of horseradish 



METALS PROPER. 



GOLD. 



Gt, In what state does gold occur in nature 1 

.A. Either pure, or alloyed with silver or copper. 

Gl. Where are gold mines found 1 

A. In Transylvania, South America, and in the United States. 

Gt. How is gold obtained from its impurities '? 

A. By the process of amalgamation and distilling off the 
mercury. Pure gold may be obtained by precipitating it from 
a solution of the coin in nitro-muriatic acid, by means of proto- 
sulphate of iron. 

Gt. Can you give the properties of gold 1 

A. It is of a yellow colour, the most malleable and ductile of 
all the metals, possesses but little affinity for oxygen or sulphur, 
and its specific gravity is 19.3. 

7^ 



4 3 CATECHISM ON CHEMISTRY. 

Q. What is the proper solvent ? 

A. Chlorine is the only solvent of gold. The efficacy of 
nitro-muriatic acid as a solvent of gold, is owing to the evolu- 
tion of dilbrine. 

Q. Can you enumerate some of the compounds formed with 
gold ? 

A. There are two oxides, two chlorides, and a sulphide. 
Gold combines with nearly all the metals, and energetically 
with mercury. 

Q. What is the best test for gold 1 

A, Proto-muriateof tin, v^^hich furnishes a purple precipitate 
which is a compound of peroxide of tin and oxide of gold. 

Q,. What is fulminating gold 1 

A. The aurate of ammonia. 

PLATINUM. 

d. What is the origin of platinum ^ 

A. It is found in South'America in native metallic grains, 
either alone or associated with other metals. 

Ct. How is the solid metal obtained 1 

A. By dissolving the native grains in nitro-muriatic acid, 
and precipitating the solution by means of muriate of ammonia. 
This precipitated, which is the ammoniacal muriate of platinum, 
is then to be exposed to intense ignition, which develops the 
metal in a divided state. The minute particles thus obtained 
are subjected to intense pressure, by which they are made to 
cohere. 

Gt. Can you give the properties of platinum ? 

A, It is white like silver, though inferior in lustre, malleable 
and ductile, very infusible, soluble in nitro-muriatic acid, and is 
the heaviest metal. Specific gravity 21 J. 

Q. Are there any compounds with platinum '? 

A. There are two or more oxides, two chlorides and a sul- 
phide. 



CATECHISM ON CHEMISTRY. 79 

Gl. What are precipitants of platinum ? 

A. Ammonia, and a solution of a salt of potash form, with 
the muriate, a yellow precipitate. The former produces muriate 
of platinum and ammonia ; the latter, what is called chloro- 
platinate of potash. 

d. What is the best test for platinum? 

A. Protorauriate of tin, which produces a claret coloured pre- 
cipitate. 

Q. What other metals are frequently found in company with 
the native grains of platinum 1 

A. Osmium, palladium, rhodium and iridium. 

SILVER. 

Q. In what states does silver occur in nature ? 

A. Metallic, nearly pure, and as a sulphide, chloride, iodide 
and carbonate; but most abundant is the argentiferous galena. 
Silver is likewise alloyed with gold and other metals. 

Gt. Where are silver mines found ? 

A. In Mexico, Peru, Norway, Hungary and Transylvania. 
No mines in the United States, but it is found as argentiferous 
galena in several localities. 

Q. How is metallic silver extracted from its ores ? 

A. By the processes of amalgamation and cupellation. Pure 
silver may be obtained by dissolving the coin in nitric acid, and 
evaporating by heat. 

Q. What are the properties of silver '? 

A. It is of a white colour, brilliant, very malleable and duc- 
tile, very tenacious, fusible at a red heat, insusceptible of oxi- 
dizement in the air, possesses a strong affinity for sulphur and 
chlorine, the former of which tarnishes it, is one of the best 
conductors of heat, and its specific gravity 10.5 

Q. How many oxides of silver are there ? 

A. Two : a protoxide and peroxide, 

Q. What is the proper solvent of silver '? 



OU CATECHISM ON CHEMISTRY. 

A. Nitric acid, a part of which oxidizes the metal, pnd the 
oxide thus formed is dissolved by the other part forming nitrate 
of silver in solution. 

d. What is lunar caustic^ 

A. Fused nitrate of silver 1 

Gl. Does sulphuric acid react with silver '? 

A. Only at a boiling heat, by which a sulphate is formed. 

Gl. Is silver soluble in nitro-muriatic acid ? 

A. No; because an insoluble chloride would be formed. 

Gl. What is the best test for silver 7 

A. Chlorine ; forming an insoluble chloride ; consequently 
the muriates form good tests for silver. 

Gl. What are the properties of the chloride'? 

A. Precipitated it is white, insoluble in water, sparingly so- 
luble in acids, but is soluble in ammonia, decomposed by hydro- 
gen when evolved in contact with it, and by fusion with tin, 

zinc, or the fixed alkalies, or when boiled in water with pieces 
of iron. 

Gl. What are the precipitants of silver *? 

A. The muriates, phosphates, chromates, arsenites, arseni- 
ates, copper and mercury. 

Q,. What is fulminating silver'? 

A. Cyanide of silver, formed by mixing the metal with cyan- 
hydric acid. 

MERCURY. 

Gl. How does mercury occur in nature 1 

A. In its metallic state, either alone or amalgamated with 
silver, and as an oxide, chloride and sulphide. The sulphide 
known in commerce as the native cinnabar, is the most abun- 
dant ore of mercury. 

Gl. Where is mercury found to exist 1 

A, In Spain, Hungary, Asia and South America. 

Gl. How is metallic mercury procured '? 



CATECHISM ON CHEMISTRY. 81 

A. By distilling native cinnabar with iron filings or lime, 
which detain the sulphur. 

Q. What are the properties of mercury 1 

A. It is of a silver white colour, its freezing point is at 39^ 
below zero, its boiling point is at 656° ; it slightly tarnishes in 
the air, and it is the only metal that is liquid at the ordinafy 
temperatures of the atmosphere. Its specific gravity is 13.6, 
and its atomic weight is represented by 200. 

Q. How many oxides of mercury are there '? 

A. Two ; a protoxide and deutoxide. 

Q. How may the protoxide be formed ? 

A. By exposing mercury to mechanical agitation in the air, 
or by mixing calomel briskly with pure potassa in excess, and 
washing with water. This oxide is also obtained by precipi- 
tation from a solution of the proto-nitrate of mercury, by means 
of pure alkalies. 

Gt. What properties characterize this oxide 7 

A. It is of a black colour, insoluble ; it is medicinal per se, 
and forms, by union with acids, medicinal salts. It is called, 
from its black colour, the black oxide of mercury. This oxide 
enters the composition of the blue mass and the mercurial 
ointment. 

Q,. How are the blue mass and mercurial ointment made 1; 

A. The former by rubbing mercury with the conserve of 
roses, until the globules disappear; the latter by rubbing mer- 
cury with lard, in which case only part of the mercury is sup- 
posed to be oxidized. 

Q,. How is the peroxide of mercury formed *? 

A. Either by calcining mercury in the air, or decomposing 
the nitrate by intense heat. This oxide is called, in popular 
language, red precipitate. 

Q,. What are the properties of this oxide 1 

A. It is of a scarlet red colour, slightly soluble in water, 
forming a solution of an acrid taste. This oxide is poisonous, 
and forms poisonous salts. 



82 CATECHISM ON CHEMISTRY. 

CI. How many sulphides of mercury '? 

A. Two; a simple and a bisulphide. 

Q,. How is the simple sulphide formed ? 

A. By passing sulphydric acid gas through a solution of the 
protonitrate of mercury. It is of a dense black colour. 

"Q,. How is the bisulphide formed 1 

A. By fusing sulphur with about six times its weight of mer- 
cury. When thus formed, it is the artificial cinnabar. It is 
of a gray colour, and when levigated it is converted into ver- 
milion, which is red. 

Q,. What is Ethiop's mineral '? 

A. It is a mixture of the bisulphide with sulphur. It is 
made by triturating together equal weights of mercury and 
sulphur. 

Gt. What are the salts of mercury ? 

A. The nitrates, sulphates, muriates and phosphates. 

Q. How is the nitrate formed 1 

A. By the action of nitric acid on mercury. If the metal be 
in excess, protonitrate is formed ; but if the acid be in excess, 
the deuto or pernitrate results. 

Q. In what respect do these nitrates differ'? 

A. The crystals of the protonitrate are white ;• those of the 
deutonitrate are j^ellow. 

Q. Is there any reaction between cold sulphuric acid and 
mercury '? 

A. No ; but, when boiled on mercury, the acid is decom- 
posed ; one portion. yielding oxygen to the metal, v;hile the 
other, uniting with the oxide thus formed, results in the sul- 
phate. 

Q. How is the protosulphate formed '? 

A. By heating two parts of mercury with three of sulphuric 
acid, so as to form a slow effervescence. For medicinal pur- 
poses it is made by triturating metallic mercury with the bisul- 
phate of the deutoxide. 

Q,. Is this salt of interest ^ 



CATECHISM ON CHEIHISTRY. 83 

A. Yes ; because it is used for making calomel. It is white 
and insoluble. 

Q,. How is the bipersulphate of mercury made'? 

A. According to the Pharmacoposia of the United States, it 
is prepared by boiling two pounds of mercury with thirty 
ounces of sulphuric acid, until the mass is dry. 

Q. Of what interest is this salt 7 

A. It is used for making corrosive sublimate. It is a fine 
white salt, and more soluble than the protosulphate. From 
this sulphate, the United States Dispensatory gets the proto- 
sulphate for the purpose of making calomel. 

Q,. How is the conversion of this salt into the protosulphate 
explained ? 

A. When it is triturated with metallic mercury, the metal is 
oxidized at the expense of one equivalent of its oxygen, with 
which one equivalent of the sulphuric acid combines to form 
one equivalent of protosulphate of mercury. Hence one equiva- 
lent of the bipersulphate is converted into two equivalents of 
the neutral protosulphate. 

Gt. What is formed by throwing the bipersulphate into 
water'? 

A. A yellow precipitate, commonly called turpeih mineral. 

Gl. What is turpeth mineral'? 

A. According to general consent, it is considered to be a per- 
sulphate of mercury, that is the neutral sulphate of the peroxide, 
usually called the subsulphate. Opinion is not uniform as to 
the manner in which the formation of turpeth mineral should 
be explained. This change is generally supposed to consist in 
the separation, by the action of the water, of one equivalent of 
sulphuric acid, which remains in the solution; and upon this 
supposition, the preparation under consideration would be 
simply a persulphate of mercury, consisting of one equivalent 
of acid and one equivalent of peroxide of mercury. But it 
would appear, that the water separates something more than 
the sulphuric acid, for the solution is found to contain mercury, 



84 CATECHISM ON CHEMISTRY. ' 

and when evaporated , will yield a white crystalline salt. Ac- 
cording to Turner, the hot water retains some of the sulphate 
in solution, together with free sulphuric acid. Berzelius is of 
opinion that the bipersulphate is decomposed by the water into 
supersulphate, which remains in solution, and a subsesquisul- 
phate, which, being insoluble, precipitates as the turpeth. An- 
other explanation is that given by Dr. Hare, which, while it 
reconciles the facts, is at the same time more simple and satis- 
factory. He assumes the dry mass, which yields the turpeth 
by washing, to be a mixture of bisulphate and neutral-sulphate, 
and that the former is dissolved while the latter remains in so- 
lution. 

Q. Is mercury soluble in muriatic acid 1 

A. No. But the oxide of mercury is soluble in this acid, 
which results in a chloride of the metal, 

Q. What are the chlorides of mercury 1 

A. There are two ; the protochloride or calomel, and the 
deutochloride, or corrosive sublimate. The former of these 
is designated as the mild or weak chloride, and the latter as 
the corrosive chloride of mercury, 

Q. How is calomel prepared ? 

A. There are two modes of obtaining calomel, one by subli- 
mation, which is the dry v/ay, the other by precipitation, or 
the moist way. 

Q. How is calomel made by sublimation'? 

A. Either by subliming metallic mercury with corrosive 
sublimate, or by the reaction between chloride of sodium and 
Ihe protosulphate of mercury, when they are sublimed together. 

Q. What is the process of the United States Pharmacopoeia'? 

A. Boil two pounds of mercury with thirty ounces of sul- 
phuric acid in a glass vessel until the sulphate is left dry. Rub 
this when cold with two pounds of mercury in an earthenware 
mortar, so that they be thoroughly mixed; then add chloride 
of sodium, and rub it with the other ingredients till the glo- 
bules disappear ; afterwards sublime. Reduce the sublimed 



CATECHISM ON CHEMISTRY. 85 

mass to a very fine powder, pass it through a sieve, and wash- 
ing it repeatedly in boiling distilled water, till this affords no 
precipitate upon the addition of water of ammonia. 

Q,. What is the rationale of the formation of calomel 1 

A. If, for the sake of simplicity, we take a single equivalent 
of the reacting materiaIvS, it may be thus explained : One • 
equivalent of protosulphate of mercury consists of one equiva- 
lent of sulphuric acid, one of oxygen, and one of mercury; and 
one equivalent of chloride of sodium consists of one equivalent 
of chlorine, and one equivalent of sodium. The one equiva- 
lent of chlorine unites with one equivalent of mercury, and 
forms one equivalent of calomel, which sublimes, while the 
single equivalent of each, sulphuric acid, oxygen and sodium, 
combines together, to form one equivalent of dry sulphate of 
soda as a residue. Hence, it is essential in order to form calo- 
mel, that equal equivalent proportions of the materials should 
be employed, and that in giving the exact rationale as made by 
the direction of the United States PharmacopcEia, it should be 
borne in mind, that two equivalents of the protosulphate being 
present, two equivalents of chloride of sodium are required, and 
which form two equivalents of calomel, and two equivalents 
of dry sulphate of soda. 

Q. Why, in this case, do we presume two equivalents of 
the protosulphate to be present '? 

A. Because one equivalent of bipersulphate is converted into 
two equivalents of the protosulphate as preliminary, by the 
United States formula: therefore, it is better, for the sake of 
perspicuity and consistency, to assume such a composition. 

Q. What are the properties of calomel '? 

A. It is a white crystalline powder, compact, tasteless, inso- 
luble, blackened by long exposure to light, and becomes black 
or brown by trituration with alkalies or lime water. 

Q. What are tests of its purity 1 

A. Its complete sublimation by heat, and striking a black 
colour free from a reddish tinge, by the contact of fixed alkalies. 
8 



86 CATECHISM ON CHEMiSTRY. 

Q. How is calomel prepared by precipitation ? 

A. By adding to a solution of protonitrate of mercury, mu- 
riate of soda, (common salt.) 

Q. How is corrosive sublimate formed ? 

A. Either by heating- mercury in chlorine gas, or by dis- 
solving the deutoxide of mercury in muriatic acid* In the for- 
mer case chlorine combines directly with mercury; in the 
latter, the hydrogen of the acid and the oxygen of the oxide 
combine together to form water, which, evaporating, leaves 
chlorine in union with the mercury, as a biperchloride or cor- 
rosive sublimate. For medicinal purposes, corrosive sublimate 
is formed by the complex afSnity which operates when chloride 
of sodium and bipersulphate of mercury are sublimed together. 
The quantities required for mutual decomposition are two 
equivalents of chloride of sodium, consisting of two equivalents 
of chlorine and two equivalents of sodium; and one equivalent 
of bipersulphate of mercury, consisting of one equivalent of 
mercury, two equivalents of oxygen, and two equivalents of 
sulphuric acid. The two equivalents of chlorine combine with 
the one equivalent of mercury, to form one equivalent of corro. 
sive sublimate, which is sublimed, and the two equivalents 
severally, of sodium, oxygen and sulphuric acid, by their union, 
form two equivalents of dry sulphate of soda as a residue, 

Q. What are the properties of corrosive sublimate ? 

A. It is of a white colour, crystalline, semi-transparent, 
heavy, of an acrid and corrosive taste, soluble in water, alcohol, 
and ether; it forms a very soluble compound with muriate of 
ammonia, and is a virulent poison. 

Ct. What are antidotes for poisoning from corrosive subli- 
mate ? 

A. Albumen and gluten, which convert it into calomel. With 
this view, in case of poisoning, eggs should be largely admi- 
nistered, and, if they be not at hand, wheat fiour mixed with 
water should be substituted. 

CI. What are the tests for corrosive sublimate, or salts of 
mercury 1 





CATECHISM ON CHEMISTRY. 87 

A. Sulphydric acid, (sulphuretted hydrogen;) lime water; the 
pure and carbonated alkalies; idohydrate of potash; ammonia; 
protomuriate of tin ; and nitrate of silver. Sulphydric acid pre- 
cipitates the black sulphide of mercury, lime water a yellow 
peroxide of mercury, and the same is precipitated by the pure 
fixed alkalies; the carbonated alkalies give a brick red preci- 
pitate of the carbonate of the peroxide. Idohydrate of potash 
precipitates the deutoiodide of mercury, which is of a pale scar- 
let colour, and is not liable to ambiguity, as there is no other 
iodide resembling it. Ammonia throws down a white precipi- 
tate, which is the precipitatum album of the shops: it consists 
of muriate of ammonia and peroxide of mercury, each one 
equivalent. Protomuriate of tin causes at first a white, after- 
wards a grayish black coloured precipitate of metallic mercury 
in a divided state. Nitrate of silver causes a heavy white pre- 
cipitate of chloride of silver, which blackens on exposure to 
light; this test can only detect the chlorine of the chloride, but 
not the mercury. In addition to these there are other tests, 
such as cyanoferrite of potash, which gives a white precipitate 
of the cyanoferrite of mercury; and a bright iron plate be- 
comes covered with a grayish film by exposure in a mercurial 
solution. A polished piece of gold, moistened with a mercurial 
solution, when touched through the solution with a piece of 
iron, becomes of a silvery white. The mercurial salts are all 
volatilized b)^ heat. 

Q. Does cyanogen combine with mercury ? 

A. Yes. There is a bicyanide obtained by boiling the red 
oxide of mercury with Prussian blue. 

COPPER. 

Q. How is copper found in nature ? 

A. In its metallic state; and as an oxide; a carbonate; and 
a sulphide. 

Q. IJow is the metal reduced 7 



88 CATECHISM ON CHEMISTRY. 

A. By first heating the sulphide, by which the sulphur is 
volatilized, and the metal oxidized; the resulting oxide is then 
reduced by means of charcoal. Precipitated from solution, by 
means of iron, copper may be obtained in its greatest purity. 

Q. What are the properties of copper ? 

A. It is of a red colour, very malleable and ductile, next to 
iron in tenacity, a good conductor of caloric, and fusible at a 
white heat. Its specific gravity is 9, 

Q. How many oxides of copper are there 1 

A. Three; a protoxide, a peroxide, and a dioxide. The pro- 
toxide is obtained by exposing the metal to a red heat, the 
peroxide by subjecting the nitrate to intense heat, and the 
dioxide forms the dull exterior coating of copper as it comes 
from the manufacturers. 

Q. What properties distinguish the oxides of copper ? 

A. The protoxide is of a red colour, and, with the exception 
of muriatic, it is insoluble in acids, and is attractive for oxygen. 
The peroxide is of a black colour, combines with acids to form 
salts, and with ammonia it forms an intense blue colour. 

Q. How many chlorides of copper? 

A. Two ; a fixed protochloride, and a volatile perchloride. 

Q. What are the salts of copper'? 

A. The nitrate, sulphate, muriate and carbonate. 

Q. How is the nitrate formed ? 

A. By the action of dilute nitric acid on copper. A part of 
the nitric acid is decomposed into oxygen, which peroxidizes 
the metal, and nitric oxide which escapes, as nitrous acid red 
fumes, while the other part of the nitric acid combines with the 
peroxide, to form the nitrate in question. 

Q. How is ammoniacal nitrate of copper made ? 

A. By adding aqua ammonia to a solution of the nitrate. 

Q. How is sulphate of copper formed ? 

A. Either by boiling sulphuric acid on the metal or on a 
large scale, by exposing sulphide of copper to air and moisture. 
It is in composition a bipersulphate of copper, called in com. 
mon lanofuas^e blue vitrioL 



CATECHISM ON CHEMISTRY. 89 

Q. How is the carbonate obtained ? 

A. By the double decomposition of an alkaline carbonate 
with the sulphate of copper. 

Q. How is the cuprum ammoniatum of the shops formed ? 

A. By triturating" together sulphate of copper and carbonate 
of ammonia. 

Q. What are the alloys of copper with tin and zinc ? 

A. With the former it forms bronze and bell metal, and with 
the latter brass. 

Q. What are the tests for copper ? 

A. Iron, ammonia, cyanoferrite of potash, and idohydric 
acid. Iron precipitates pure copper, ammonia, a blue, and the 
cyanoferrite of potash, a rich reddish brown precipitate of 
cyanoferrite of copper. Idohydric acid produces the insoluble 
iodide of copper. 

LEAD, 

Q,. In what state in lead found in nature ? 

A. As an oxide, sulphide and salt. The most abundant ore 
is the native sulphide, known by the name of galena. 

Q. How is the metal reduced ? 

A. By heating- galena with charcoal. 

Q. What are the properties of lead '? 

A. It is of a blueish colour, tarnishes on exposure to the air, 
it is soft, flexible, inelastic, ductile in large masses, inferior in 
tenacity, fusible at 600°, and its specific gravity is 11.352. 

Q. How many oxides of lead are there ?- 

A. Four ; dioxide, or dross, protoxide, bioxide and red oxide 
or minium. 

Ql. How is the protoxide procured 1 

A. By collecting the pellicle off of melted lead, and is usually 
called massicot. 

Q. What are the projiferties of massicot 
8* 



90 CATECHISM ON CHEMISTRY. 

A. It is of a yellow colour, insoluble in water, and is the 
base of all the salts of lead. 

Q. What is litharge 1 

A> It is the vitrified massicot made by partially fusing the 
latter, and generally contains a little of the deutoxide. With 
resin litharge forms adhesive plaster. 

Q. What is minium or red lead 1 

A. It is a mixture of the protoxide and peroxide, generally 
made by heating litharge in the air. This is called deutoxide 
of lead by Turner, and is incapable of uniting with acids to 
form salts. 

Q. What results from the action of nitric acid on red lead 1 

A. It is resolved into protoxide and peroxide of lead; the 
former unites with the acid, the latter remains as an insoluble 
powder. 

Q. How is the peroxide formed 1 

A. By treating red lead with nitric acid, which dissolves 
the protoxide and leaves the peroxide. This oxide is of a pure 
brown colour, does not unite with acids, and is resolved by heat 
into protoxide of lead and oxygen gas. 

Q. Is there a sulpliide of lead ? 

A. Yes. It is formed either by precipitating a solution con- 
taining lead, by means of sulphydric acid gas, or fusing lead 
and sulphur together. 

Q. Are there a chloride and iodide of lead 1 

A. Yes. The former may be obtained by adding muriatic 
acid to a solution of sugar of lead, the latter by adding idohydric 
acid to the same salt. 

Q. What are the salts of lead '? 

A. The nitrate, sulphate, carbonate, and acetate of lead. 

Q. How are the nitrate and sulphate formed. 

A. By the action of nitric acid on lead we obtain the former, 
and by boiling sulphuric acid on the metal the latter is 
obtained. 

Q. How is the acetate (sugar of lead) formed ? 



CATECHISM ON CHEMISTRY. 91 

A. By the action of acetic acid on lead. It may be prepared 
either by dissolving litharge in distilled vinegar, or by subject- 
ing plates of lead to this acid, and evaporating the solution. 

Q. What is produced by the action of vinegar on lead? 

A. The carbonate of lead, which is the white lead of com- 
merce. 

Q. What is the antidote for the poisonous effects of lead ? 

A. Any soluble sulphate, which converts the lead into an 
insoluble salt. On account of its insolubility, the sulphate,© f 
lead is not poisonous. 

Q. What is the best test for lead? 

A. Sulphydric acid (sulphuretted hydrogen) which forms 
the black sulphide of lead. 

TIN. 

Q,. How does tin occur in nature '? 1^ 

A. As an oxide and sulphide. The metal is reduced from 
the ore, which is the deutoxide, by means of heat and charcoal. 

Q. What are the properties of tin 1 

A. It is of a shining lustre, very malleable and ductile, and 
produces a peculiar crackling noise when its ingots are bent to 
and fro. Its specific gravity is 7.9. Pure tin is generally 
known by the name of block tin. 

Q.. What are the habitudes of tin with oxygen, chlorine and 
sulphur ? 

A. It forms two oxides, two chlorides and two sulphides. 

Q. What is formed by the action of nitromuriatic acid on tin ? 

A. The fuming liquor of libavius, which is a bichloride. 

Cl. What is the proper solvent of tin ? 

A. Muriatic acid, which forms with it a muriate of tin. 

Q. Of what utihty is the muriate of tin ? 

A. In consequence of its affinity for oxygen, it destroys the 
colour of ink and Prussian blue. It is a test for gold and pla- 
tinura, giving a purple coloured precipitate with the former, 
and a claret coloured one with the latter. 



92 CATECHISM ON CHEMISTPcY. 

Q. How has cadmium been found ? 

A. With the ores of zinc, from which it can be obtained by 
precipitating a solution of the ore in sulphuric acid, by means 
of sulphuretted hydrogen. 

BISMUTH. 

Q. How does bismuth occur in nature ? 

A. Alloyed with cobalt and arsenic^ and as a sulphide. 

Gt. How is the metal reduced ? 

A. By the fusion of the native alloy over a heated furnace, 
with an aperture at the bottom, through which it passes into a 
vessel. • 

Q. What properties characterize bismuth? 

A. It is white, with a peculiar tint of red, brittle, not mal- 
leable nor ductile, an inferior conductor of heat, and is crystal- 
lizable. Its proper solvent is nitric acid, forming- a nitrate of 
bismuth. 

Q. What results from throwing the nitrate into water ? 

A. A fine white subnitrate, called magistry of bismuth pre- 
cipitates. If the solution contains muriatic acid, pearl white 
is formed. 

Q. Of what utility are these precipitates? 

A. As pigments to improve the complexion. 

Q. What are the habitudes of bismuth with oxygen, chlorine 
and sulphur ? 

A. There are two oxides, one chloride and one sulphide of 
bismuth. 

IRON. 

Q. How does iron occur in nature ? 

A. As a sulphide, an oxide, and alloyed with nickel and 
cobalt. Iron is very abundant, and likely forms the most uni- 
versa! colouring principle. 

Q. How is metalHc iron obtained? 



CATECHISM ON CHEMISTRY. 93 

A. By heating its native oxides with charcoal. 

Q.^ What are the properties of iron ? 

A. It is of a peculiar gray colour, ductile, malleable, attracts 
the magnet, very infusible, hard, of a fibrous texture and the 
most tenacious of all metals. Iron is capable of being hard- 
ened by heat followed by sudden refrigeration, and is suscepti- 
ble of the welding process. Its specific gravity is estimated 
at about 7.7, and equivalent, 28. 

Q. What are the habitudes of iron with oxygen, chlorine, 
and sulphur? 

A. There are two oxides, a protoxide and a sesquioxide, 
two chlorides, a protochloride and a sesquichloride and three 
sulphides. 

Gl. How is the protoxide formed ? 

A. It is formed during the solution of the metal in diluted 
sulphuric acid, which results in a sulphate of that oxide: or, 
it may be precipitated in the state of a white hydrate by means 
of an alkaline solution. It cannot be isolated. 

Q. How is the sesquioxide obtained ? 

A. It may be formed by dissolving iron in nitro-rauriatic 
acid, and adding an alkali, or by heating the sulphate or 
nitrate. It occurs native as red hsematite. This oxide is of 
a red colour, and incapable of attracting the magnet. It con- 
sists of two atoms of iron to three of oxygen. 

Q. What is formed by the union of the two oxides ? 

A. The black oxide of iron, which is formed by subjecting 
the metal at a red heat to steam. It consists of the protoxide 
and peroxide, each one atom. Finery cinder is also a union 
of the two oxides. 

Q. Wiiat are the peculiarities of this oxide? 

A. It is of a dark blue colour, soluble in water impregnated 
with carbonic acid, and it attracts the magnet. 

Q,. How is the perchloride or sesquichloride formed ? 

A. By burning iron wire in an atmosphere of chlorine. 

d. What is Prussian blue 1 



94 CATECHISM ON CHEMISTRY. 

A. It is the cjanoferrite of iron, obtained by mixing- cyano- 
ferrite of potassa with a per salt of iron in excess, and washing- 
the precipitate; or, by the reaction of sulphate of iron in solu- 
tion and cyanide of potassium. The acid and oxygen take the 
potassium, while the cyanogen, by combining witli the oxide 
of iron and hydrogen, forms a cyanhydrate of iron ; at the same 
time, a cyanide of iron is formed, which, uniting with the cyan- 
hydrate, forms cyanoferrite of iron. 

Q,. How is cyanoferrite of potasli obtained ? 

A. By digesting cyanhydrate of potash (formed by mixing 
prussic acid and liquid hydrate of potash together) with the 
protoxide of iron ; or by digesting Prussian blue with potash 
until the latter is neutralized. 

Q,, What are the magnetic iron pyrites ? 

A. The proto-sulphide. It may be made by the combustion 
of iron with sulphur. The bi-sulphide is the common iron 
pyrites. 

Q. What does iron form with carbon ? 

A. Steel, cast iron and plumbago, (black lead.) Black lead 
is carbon in unison with about 5 per cent, of iron. Steel is 
made by heating pure iron with charcoal in ovens without 
access of air. By fusion, steel forms cast iron. 

Q,. What are some of the most important salts of iron? 

A. The sulphate, carbonate, phosphate and muriate. 

Gl. What properties distinguish the salts formed with the 
protoxide from those formed with the sesquioxide of iron ? 

A. The prosalts are of a green colour, crystallizable, and 
insoluble in alcohol ; the persalts or sesqui salts are of a brown 
colour, uncrystallizable, and soluble in alcohol. 

Q. How is the protosulphate of iron formed ? 

A. By the action of diluted sulphuric acid on metallic iron, 
or by exposing the protosulphide to air and moisture, 

Q, Does carbonic, like sulphuric acid, unite with peroxide 
of iron ? 

A. No. Carbonate of the protoxide is formed by the double 



CATECHISM ON CUEMl&TIl Y. 95 

decomposition which ensues between carbonate of soda and 
protosulphdte of iron; sulphate of soda and carbonate of iron 
result: the former remaining in solution, the latter precipitated. 
•Q. How is phosphate of iron formed? 

A. By the double decomposition between phosphate of soda 
and sulphate of iron, which results in the formation of sulphate 
of soda and phosphate of iron. 

Q. How is the muriate of iron obtained ? 

A. By the action of dilute muriatic acid on iron. 

Q. Wiiat precipitates the oxides of iron from their salts in 
solution. 

A. The pure and carbonated alkalies throw down the hy- 
drate of the peroxide of iron from solutions of the persalts, and 
the pure alkalies, the hydrate of the protoxide, from solutions 
of the salts of the protoxide of iron. 

Gl. What are the tests for iron ? 

A. Cyanoferrite of potash, galls and other vegetable astring- 
ents containing tannin, succinic and meconic acids. The 
precipitate produced by the cyanoferrite, is of a blue colour 
and is the cyanoferrite of iron, (Prussian blue ;) that from galls, 
is an ink coloured tannogalate of iron ; succinic acid produces 
a brown coloured succinate, and meconic acid gives a red mfi- 
conate of iron. 

ZINC. 

Gl. In what states is zinc found in nature'? 

A. As a sulphate, silicate, carbonate, and sulphide. The 
silicate and carbonate are known in mineralogy under the 
name of calamine, and the sulphide as blende. 

Q. How is the metal reduced ? 

A. By healing its oxide, which is obtained by roasting cala- 
mine or blende with charcoal. 
• Q. What are the properties of zinc ? 

A. It is brilliant, of a white colour, with a slight leaden hue, 



96 CATECHISM ON CHEMISTRY. 

of a crystalline structure, and lamellated texture, fusible, and 
soluble in nitric and muriatic acids. The specific gravity of 
zinc is 7. 

a. \VhGt i§ butter of zinc ? 

A. It is the chloride, formed by subjecting the metal to 
chlorine gas. 

Q. What are flowers of zinc ? 

A. It is the protoxide of zinc. This oxide is formed daring 
the combustion of the metal in the air, but the better mode is 
to precipitate it from a solution of the sulphate by liquid am- 
monia. 

Q, What is an important salt of zinc? 

A. The sulphate; or white vitriol. It is obtained either by 
roasting blende, or by the action of sulphuric acid on metallic 
zinc. 

Q. What is produced by having a piece of zinc suspended 
in a solution of acetate of lead ? 

A. A precipitate of lead, called arbor saiurni. 

ARSENIC. 

■ Q, In what state does arsenic occur in nature? 

A. As an oxide, sulphide and alloy. It is sold in commerce 
under the name of cobalt, which is considered as an oxide of 
arsenic. 

Q. How is the metal reduced ? 

A. By heating intensely with charcoal either the white 
oxide of arsenic or native cobalt. 

Q. What are the properties of metallic arsenic ? 

A. It is a bright crystalline solid, brittle, and when heated 
before the blow pipe, it burns before it fuses, emitting copious 
white fumes which have the odour of garlic. 

Q. What is the white arsenic of the shops ? 

A. It is the white oxide, obtained by subliming the native 
cobalt or metallic arsenic, and is called arsenious acid. 



CATECHISM ON CHEMISTRY. ' 97 

Q. What are the properties of arsenious acid? 

A. It is a white powder, soluble in water, reddens vegetable 
blues, and combines with salifiable bases, forming salts which 
are termed arsenites. It is composed of arsenic, one equiva- 
lent, to oxygen one and a half. It is very poisonous. 

Q. What is arsenic acid ? 

A. It is the peroxide of arsenic, obtained bj^ the action of 
rjitromuriatic acid on the metal, or by deflagrating the latter 
with nitre. 

Q. What properties distinguish this oxide ? 

A. It is white, much more soluble than arsenious acid, of a 
sour taste, and forms with salifiable bases, arseniates, 

Q. What preparation of arsenic is used in medicine? 

A. Fowler's solution, which is obtained by boiling pearl- 
ash on the white oxide of arsenic. According to the United 
States Pharmacopioea, it is made hy boiling arsenious acid and 
carbonate of potash, each sixty-four grains, with a pint of dis- 
tilled water until the acid is entirely dissolved. To the solu- 
tion, when cold, add four fluid drachms of the compound 
spirit of lavender, and afterwards sufficient distilled water to 
make up the measure of a pint. It is an arsenite of potash in 
solution, the carbonic acid being expelled. 

Q, What results from the deflagration of arsenious acid 
with nitre ? . 4 

A. An arseniate of potash, a salt formed by the union of 
arsenic acid and potash. 

Q. What properties characterize the arsenites and arseniates? 

A. Excepting those of potash, soda and ammonia, the 
arsenites and arseniates are very sparingly or quite insoluble 
in water, but soluble in nitric acid, and most other acids with 
which their bases do not form insoluble compounds. They are 
decomposed by copper and silver, and destroy the colour of the 
iodide of starch. 

Q. What is formed by exposing arsenic to chlorine gas? 

A. A liquid chloride, analogous to the bi-chloridc of tin. 
9 



98 CATECHISM ON CHE3I13TFIY. 

Q. EIow many native sulphides are there ? 

A. Two, one called realgar, which is crystalline, of a ruby 
red colour, and is a proto sulphide, the other, called orpiment, 
which is of a j^ellow colour, and is considered as a persulphide 
of arsenic. According to Turner, there are three sulphides, 
and orpiment is regarded by him as the sesqui or intermediate 
one. Orpiment is tjie colouring principle of a paint called 
king's yellow. 

Q,. Can this sulphide be produced by artificial means? 

A. Yes; it is made by passing sulphuretted hydrogen gas 
through a solution containing arsenious acid. 

Q,. Is there a compound of arsenic with hydrogen ? 

A. Yes ; it is a solid, its vapour burning with a pale bluish 
white flame. 

Q. What are the tests for arsenious acid ? 

A. Lime water, ammoniacal nitrate of copper, ammoniacal 
nitrate of silver, sulphydric acid, (sulphuretted hj^drogen,) and 
the reduction of the metal itself. Lime water precipitates the 
white arsenite of lime, which is soluble in all acids that are 
capable of dissolving lime. The ammoniacal nitrate of copper 
gives an apple green precipitate, which is an arsenite of cop- 
per, called Scheele's green; and the ammoniacal nitrate of 
silver gives a bright yellow arsenite of silver. Sulphuretted 
hydrogen produces a yellow precipitate, which is a pure orpi- 
ment or sesqui-sulphide of arsenic. 

Gl. What is the best precipitant for arsenic acid ? 

A. The ammoniacal nitrate of silver, which results in a brick 
red arseniate of bilver. 

Q. What is the best mode of detecting arsenic in a«tomach 
which is suspected to contain it ? 

A. By subjecting the mass or contents of the stomach to 
heat, with powdered charcoal, in a glass tube, metallic arsenic 
will be evolved, which sublimes in crystals. When it is much 
intermingled with other matter, it is preferable to evaporate 
a solution of the mass to dryness, and then digest in nitric 



CATECHISM ON CHEIVIISTRY. 99 

acid, until this acid is expelled or decomposed, by which ell 
the organic matter will be destroyed, and the arsenious con- 
verted into arsenic acid. It may ihen be subjected to the 
common tests, or reduced by means of heat and charcoal. 

Q. Why is lime water objectionable as a test for arsenic? 

A. Because it yields white precipitates, with carbonic, phos- 
phoric, oxalic, and tartaric acid, and the arsenite is so light a 
powder as to escape detection in milk or gelatinous solutions. 

Q. What renders the ammoniacal nitrate of silver or copper 
fallible tests for arsenious acid? 

A. Phosphoret of silver is yellow, like the arsenite, and 
many substances containing no arsenic give to the copper a 
green colour. 

Q. Is the colour of the precipitate produced by sulphuretted 
hydrogen, peculiar to arsenic alone ? 

A. No; with antimony, tin, cadmium and selenium, this 
gas gives yellow coloured precipitates. 

■ ANTIMONY. 

Q. In what state is antimony found in nature ? 

A. As a metal, and a sulphide. The antimony of the shops 
is a sulphide. Pure antimony is usually designated by the 
name of regulus of antimony. 

Q. How is metallic antimony reduced ? 

A. Either by heating the sulphide with iron filings, which 
detains the sulphur, or by mingling the sulphide with two- 
thirds of its weight of bitartrate of potash, and one-third of its 
weight of nitre, and deflagrating the mixture in a red hot cru- 
cible. The metal being oxidized, and the sulphur acidified by 
the oxygen of the nitre, the resulting oxide of antimony is re- 
duced by the carbon of the tartaric acid. The principal mines 
from which antimony is obtained are in France and Germany. 

Q. What properties characterize metallic antimony ? 

A. It is brilliant, of a bluish white colour, brittle, of a crys- 



100 CATECHISM ON CHEMISTRY. 

talline structure, odorous when rubbed, fuses below a red heat, 
and when fused and thrown upon a board it scintillates. The 
specific gravity of antimony is 6.7, and its equivalent weight is 
represented by 44. 

Q. What are the habitudes of antimony with oxygen, sul- 
phur and chlorine ? 

A. There are three oxides, three sulphides, and three chlo- 
rides of this metal. 

Q. Which is the most important oxide of antimony ? 

A. The sesquioxide; it is this oxide only w^hich forms salts 
with acids, and is medicinal. The deutoxide and peroxide are 
acids; the former is called antimonious, and the latter anti- 
monic acid. 

Q. How is the sesquioxide obtained ? 

A. There are several modes of forming this oxide. The pro- 
cess now generally adopted is to wash the precipitate, formerly 
called powder of Algaroth, which is made by pouring the ses- 
quichloride or muriate of antimony into water. When the 
chloride or butter of antimony is poured into water, it becomes 
a muriate, which is decomposed by the w^ater into muriatic 
acid, and sesquioxide of antimony, the latter falling down as a 
submuriate, because it contains a little muriatic acid. To ob- 
tain the sesquioxide in its greatest purity, it is best to digest 
this precipitate with a dilute alkaline solution, until it is free 
from acid. This oxide is called by the Dublin and United States 
Pharmacopoeias nitromuriatic oxide of antimony, in conse- 
quence of their making the chloride by dissolving the sulphide 
of antimony in muriatic with a small quantity of nitric acid. 
This oxide may also be obtained by precipitation from tartar 
emetic in solution, by means of carbonate of potash or soda. 

Q. What are the properties and uses of this oxide ? 

A. It is a white powder, with somewhat of a dirty appear- 
ance, fusible at a red heat yielding a yellow fluid, and it is 
used for making tartar emetic. 

Q. How is antimonious acid procured? 



CATECHISM ON CHEMISTRY, 101 

A. By digesting meiallic antimony, or its oxide, in nitric' 
acid, and exposing the resulting hydrate of the peroxide to a 
strong heat. This oxide is also obtained by exposing metallic 
antimony, or the sesquioxidc, to intense heat. 

Q. What properties distinguish this oxide ? 

A. It is white, and very infusible, being less fusible and 
more volatile than the sesquioxide. It sublimes by heat, and 
condenses into crystals of a silvery whiteness, called argentine 
flowers of antimony. It is insoluble in water, and likewise in 
8ci-ds after being heated to redness, and unites with alkalies to 
form antimonites. 

Q. How is antimonic acid procured ? 

A. By digesting the metal in strong nitric acid, or dissolving 
it in nitromuriatic acid, and pouring the solution into water, 
there is precipitated the hydrate of the peroxide, which is of a 
white colour and soluble. By subjecting this to the tempera- 
ture 500° or 600°, it is converted into a pure peroxide. 

Q. What is the character of this oxide ? 

A. It is of a yellow colour, insoluble in water and muriatic 
acid. 

Q. What is the alleged composition of the compounds of 
antimony and oxygen ? 

A. The nitromuriatic oxide or sesquioxide consists of two 
atoms of the metal to three of oxygen, antimonious acid, or 
the deutoxide consists of two atoms of metal to four of oxj^gen; 
and the peroxide, or antimonic acid, consists of two atoms of 
metal to five of oxygen. 

Q. What are the chlorides of antimony ? 

A. Asesquichloride, a deuto or bichloride and a perchloride. 

Q. How is the sesquichloride made ? 

A. Either by burning antimony in chlorine gas, by distilling 
the sulphide with corrosive sublimate, or dissolving the sesqui- 
sulphide in dilute muriatic acid. The United States Dispensa- 
tory directs the following: — Take of the sulphide 2 ounces, mu- 
yiatic acid 12^ fluid ounces, nitric acid a drachm, water a gallon. 

9^ 



102 CATECHISM ON CHEMISTRY. 

Having- mixed the acids, add 'by deg^rees the sulphide until 
effervescence ceases; then boil one hour. The oxygen of the 
water in this process converts the metal into sesquioxide, which, 
uniting with the acid, forms muriate of antimony in solution, 
while the hydrogen, uniting with the sulphur, forms sulphy- 
dric acid, the extrication of which causes the effervescence. 
Hence we have a solution of sesquichloride of antimony. 

Q. What are the properties of this chloride ? 

A. It is a soft solid, of a yellow white colour, and semi-trans- 
parent, crystallizes on cooling, deliquesces on exposure to the 
air, and when mixed with water, it is converted into muriatic 
acid and sesquioxide of antimony. From its peculiar consist- 
ence it is called butter of antimony. 

Q. What is formed by passing dry chlorine over heated an- 
timony ? 

A. The bichloride. It is a transparent volatile liquid, which 
emits fumes on exposure to the air. 

Q. What is the perchloride ? 

A. It is two equivalents of metal to five equivalents of chlo- 
rine. 

Q. HovvT is the simple or sesquisulphide of antimony formed 7 

A. By fusing antimony with sulphur. 

Gl. What is formed when sesquisulphide of antimony is 
boiled with an aqueous solution of potash ? 

A. A liquid is formed, which, on cooling, yields a reddish 
brown precipitate, known under the name of kermes mineral. 
According to Thompson, kermes mineral is a sulphohjdrate 
of antimony, or hydrosulphuretted oxide of antimony. Gay- 
Lussac regards it as an oxysulphide ; that is, a combination of 
the sulphide with the protoxide of antimony. Assuming the 
latter composition, its formation is thus explained : — By the 
mutual reaction of water, and a part of the sulphide of anti- 
mony, sulphydric acid (sulphuretted hydrogen) and sesquioxide 
of antimony are formed ; the former of which unites to the 
potassa as a hydrosulphate of potassa in solution, and the latter 



CATECHISM ON CHEMISTRY. 103 

to the remainder of the sulphide to form the kermes. This 
being- very soluble at the boiling temperature in the sulphohy- 
drate of potash, but at common temperatures being much less 
so, it is in part precipitated on the cooling- of the solution. 

Q. What properties characterize kermes mineral ? 

A. It is a dark brown powder, which becomes lighter on 
exposure to the air, and is decomposed by muriatic acid and 
heat, with the extrication of sulphuretted hydrogen. Accord- 
ing to Thompson, the kermes consists of antimony, sulphur, 
oxygen and hydrogen each one equivalent. 

Q,. What results from the addition of an acid to the alkaline 
solution? 

A. A further precipitation ensues. This precipitate mixed 
with the kermes is known in pharmacy as the golden sulphur 
of antimony. Jn consequence of the complicated changes 
going on in the solution fi-om which kermes is precipitated, by 
the addition of an acid, sulphur is set free with extrication of 
sulphuretted hydrogen. Thompson regards the composition of 
the golden sulphur as kermes mineral, with one equivalent of 
s ulphur. 

Q. Hov/ is the rationale of this second precipitation ex- 
plained ? 

A. By supposing the solution which remains after the 
kermes is throwm down, to absorb oxygen ; by which part of 
the sulphuretted hdyrogen is decomposed, its hydrogen com- 
bluing with the oxygen absorbed, and its sulphur, by uniting 
with the remaining, undecomposed sulphydric acid, (sulphur- 
etted hydrogen,) results in the formation of sulphuretted hydro- 
sulphate of potash. Assuming these changes to have taken 
place, it may be explained thus : on addition of the acid which 
causes neutralization of the solvent of the kermes, more of the 
latter will fall down ; and from the consequent decomposition 
of the sulphuretted hydro-sulphide, sulphuretted hydrogen and 
sulphur are set free, the former being evolved, the latter pre- 
cipitated. 



104 CATECHISM ON CHEMISTRY. 

Q. What are the striking" properties of the golden sulphur ? 

A.- It is an orange coloured powder, insoluble, inodorous 
burns with a greenish blue flame, giving off sulphurous acid. 
It is soluble in solutions of the caustic fixed alkalies. 

Q. How is the bi-sulphide of antimony obtained ? 

A. By the action of sulphuric acid on peroxide of antimony. 

Q. What is the common red antimony ? 

A It is a native compound of one atom of sesquioxide of 
antimony with two atoms of the sulphide. 

Q. What is the glass of antimony ? 

A. A combination of eight parts of sesquioxide of antimony 
to one of sulphide. It is prepared by the partial roasting of 
the sulphide and subsequent fusion. 

Q. What are the properties and uses of this preparation ? 

A. It is of a vitreous appearance, of a steel gray colour, inso- 
luble in water, and used by the London college for making 
tartar emetic. 

Q, What is the crocus of antimony? 

A. It is a liver brown, opaque mass formed by deflagrating 
sulphide of antimony with nitre. Its composition, according 
to Prourit, is three parts of sesquioxide of antimony to one of 
sulphide. This is used by the Edinburgh formula for making 
tarter emetic. 

Q. What is pulvis antimonialis ? 

A. It is a combination of oxide of antimony with phosphate 
of liaie. It is the imitation powder of the celebrated Dr. James. 

Q. What is tartar emetic ? 

A. It is the tartrate of antimony and potash. 

Q. How is it obtained ? 

A. By boiling bi-tartrate of potash, (cream of tartar,) with 
either the sulphate, the glass, the crocus, or sesquioxide of anti- 
mony. The oxide is the best. By the Dublin and United 
States formulae, it is made by taking the nitro-muriaiic oxide 
of antimony, (sesquioxide,) two ounces, bi-tartrate of potash, in 
very fine powder, two ounces and a half, distilled water, eighteen 



CATECHISM ON CIIEMISTIIY. 105 

fluid ounces. Boil the water in a glass vessel; then add the 
powders previously mixed together, and boil for half an hour; 
lastly, filter the liquor through paper, and set it aside to crys- 
tallize. The principle of the formation of tartar emetic is 
merely the saturation of the excess of tartaric acid in the bi- 
tartrate of potassa, with sesquioxide of antimony. 

Q. What are the properties of tartar emetic ? 

A. It is a white salt, inodorous, of a nauseous taste, crystal- 
line, and its crystals effervesce on exposure to the air, soluble 
in water, insohible in alcohol, and decomposed by the alkalies? 
and their carbonates, and various astringent vegetable infusions. 

Q. What are tests of the goodness of tartar emetic ? 

A. By its yielding no precipitates with baryta, oxalic acid, 
nitrate of silver, or acidulous sugar of lead, and its entire solu- 
bility in a small quantity of water. The crystalline character 
of this salt is considered among the best tests of its purity. 

Q. What is the composition of this salt? 

A. It consists of one equivalent of potassa, three equivalents 
of the sesquioxide of antimony, two equivalents of tartaric acid 
and two equivalents of water. Hence it may be considered to 
consist of one equivalent of cream of tartar and three equiva- 
lents of the sesquioxide. 

Q. What are antidotes for an over dose of tartar emetic? 

A. If vomiting is not immediately induced, give a large 
quantity of cinchona in decoction or infusion ; and if this be 
not at hand, decoctions of common tea should be adminis- 
tered. 

Q. Does sulphuric acid act on antimony? 

A. No; with heat sulphuric acid oxidizes the metal by the 
decomposition of a portion of the acid, while the other portion 
combines with the oxide thus formed, as the sulphate of anti- 
mony. 

Q. How are the antimonial salts tested ? 

A. By the carbonate of potash, or soda, which precipitates the 
sesquioxide of antimony; or by sulphuretted hydrogen, which 
throws down the yellow coloured sulphide or kermes mineral. 



106 CATECHISM ON CHEMISTRY. 



METALS PROPER OF MINOR IMPORT- 
ANCE. 

Q. Enumerate a few of the metals of minor importance? 

A. Palladiufn, osmium, iridium, rhodium, &c. 

Q. Where are these found ? 

A. In union with, and accompanying' the native grains of 
platinum as imported from South America. 

Q. In what state does nickel exist % 

A. As an arsenuret, and in union with sulphur. 

Q. How is it separated from its alloys '? 

A. By the solubility of its protoxide in caustic ammonia. 

Q. What are the properties of nickeH 

A. It is white, magnetic, and in habitudes similar to cop 
per. 

Q. Where is cadmium found '? 

A. With the ores of zinc, from which it can be obtained by 
precipitating a solution of the ore in sulphuric acid by means 
of suiphydric acid. 

Q. How does chromium occur in nature ? 

A. As chromate of lead and chromate of iron. The former 
is a splendid orange colour, and used as a pigment. 

Q. What is chromic acid'? 

A. It is a peroxide of chromium. 

Q. What is the peculiarity of chromic acid ? 

A. Its producing beautiful precipitates with various metals. 

Q.. Flow is cobalt generally found ? 

A. In union with arsenic, and which may be obtained by 
heating the native oxides with charcoal. 

Q. What is formed by heating cobalt in the air ? 

A. Arsenic is expelled, leaving behind an impure oxide 
called zafFre. 



CATECHISM ON CHEMISTRY. 107 

Q. What properties distinguish cobalt? 

A It is brittle, of a reddish gray colour, and is one of the 
magnetic metals. 

Q. What can be said of columhium? 

A. It is brittle and very infusible metal, possessing but little 
importance. 

Q How is manganese found in nature ? 

A. Principally as a black peroxide. 

Q. Of what utility is this oxide % 

A. As a source for obtaining oxygen gas, as an ingredient 
in glass, and as one of the agents in evolving chlorine. 

Q. Wliat is a remarkable property of manganese ? 

A. The number of compounds it forms with oxygen. 

Q. What is chameleons mineral ? 

A. It is a compound resulting from the fusion of tlie black 
oxide with potash. The aqueous solution of this compound 
becomes successively blue, red, violet, and at last, colourless. 

Q. Enumerate some unimportant metals? 

A. Molybdenum^ titanium^ tungsten^ cerium^ uranium and 
vanadium. 



SALTS. 



Q. What is a salt defined to be ? 

A. A soluble compound, (containing one or more acid or 
corrosive ingredients,) the qualities of the ingredients being 
either neutralized or modified. — Hare, 

Q. What is the nomenclature of salts 7 

A. Acids, of which the name terminates in ous, have their 
salts distinguislied by a termination in ite. Acids, of which 
the names end in ic, have their salts distinguished by a termi- 



108 CATECHISM ON CHEMISTRY. 

nation in aie. Thus we have nitrites and nitrates — sulphites 
and sulphates, 

Q. What is a super salt ? 

A. A salt in which the acid is in excess. Thus w^e have 
super tartrate of potash, (cream of tartar.) Those salts which 
have a double proportion of acid, have the letters bi prefixed: 
thus we have bi-carbonate. 

Q. What is a sub-salt ? 

A. It is one in which the base is in excess. Thus we have 
sub-carbonate of ammonia. 

Q. What are the difTerent salts ? 

A. The chlorates, nitrates, sulphates, phosphates, carbonates,, 
chromates, iodates arid idohydrates, arseniates nnd sulpho-hj- 
drates. 

CHLORATES. 

Q. Hov*^ are the alkaline chlorates obtained? 

A. By passing chlorine ^as into an alkaline solution. The 
decomposition of water furnishes hydrogen to one portion of 
chlorine forming muriatic acid, and oxygen to another portion 
forming chloric acid; which, by the union of the two acids 
with the alkaline base, form a muriate which remains in solu- 
tion, and a chlorate which precipitates. None of the chlorates 
are found in nature. 

Q. Are the chlorates soluble in water ? 

A. Yes ; excepting that of mercury, which is sparingly so. 

Q. Are they decomposed by heat ? 

A. Yes; they give up their oxygen simply by heat, and ex- 
plode from slight causes. 

Q. What properties distinguish the chlorades ? 

A. They deflagrate violently wuth combustibles, and are 
converted into chlorides ; by the action of muriatic acid, chlo- 
rine, with protoxide of chlorine is disengaged, and by that of 
sulphuric acid, peroxide of chlorine is liberated. They are 



CATECHISM ON CHEMISTHY. 109 

mostly soluble in water. Tiie proto-chlorale of mercury is 
sparingly so. 

Q. How are nitrates prepared ? 

A. By the action of nitric acid on metals, on metallic oxide^•, 
or on carbonates. The nitrates of potash, soda, lime and mag- 
nesia occur in nature. 

Q. Are the nitrates decomposed by heat? 

A. Without exception; hence their efficacy as oxidizing 
agents. 

Q. What properties distinguish the nitrates ? 

A. The three following, namely: — 1st. By deflagrating with 
charcoal and other combustibles. 2d. By their power of dis- 
solving gold leaf on the addition of muriatic acid. 3d. By emit- 
ting, when subjected to concentrated sulphuric acid, the dense 
white fames of nitric acid. The neutral nitrates are all soluble. 

Q. What is the residuum left when a nitrate is deflagrated 
with an acidifiable combustible? 

A. The combustible united with the metallic oxide : thus, 
when charcoal is used, we have a carbonate; in case of sul- 
phur, a sulphate as a residue. 

SULPHATES. 

Q. How are sulphates formed ? 

A. By the action of sulphuric acid on the metals themselves, 
on tlie metallic oxides or their carbonates, or by double decom- 
position. Some of them, as those of lime and baryta, exist in 
nature. 

Q. Are all the sulphates soluble in water ? 

A. There are six insoluble sulphates ; namely, those of 
baryta, tin, antimony, bismuth, lead, and mercury. Those 



10 



110 CATECHISM ON CHEMISTRY. 

sparingly soluble are the sulphates of strontia, lime, zirconia, 
yttria, cerium and silver. The remainder are soluble. 

Q. Are all the sulphates decomposed by heat ? 

A. They are, excepting those of the alkalies and alkaline 
earths. 

Q. What properties distinguish the sulphates ? 

A, Their solutions are precipitated by solutions of barytes. 
Heated in contact with charcoal or hydrogen gas, they are 
converted into sulphides, which, if moistened, smell like rotten 
eggs, in consequence of sulphuretted hydrogen gas being 
formed. They are almost all insoluble in alcohol. 

Q. How can the conversion of a sulphate into a sulphide, by 
means of charcoal and hydrogen gas, be accounted for ? 

A. When heated with charcoal, the acid and the oxide are 
both deprived of oxygen, and carbonic acid is disengaged, while 
a metallic sulphide remains. A similar change is produced by 
the hydrogen gas with the formation of water, and sometimes 
sulphuretted hydrogen. 

Q. What is the best test for sulphates in solution 1 

A. Muriate of baryta in solution, which precipitates insolu- 
ble sulphate of baryta. 

PHOSPHATES. 

Q.. Are the phosphates of artificial or native origin ? • 

A. Both. Those of lime, manganese, iron, uranium, copper 
and lead, are found in nature, while others require artificial 
means for their production. 

Q. What are the distinguishing properties of the phosphates'? 

A. They give precipitates with solutions of baryta, lime, 
lead and silver. They are fusible, undecomposable by heat 
alone, and excepting those of the alkalies, insoluble in water. 

Q. What precipitate does the phosphoret of silver resemble? 

A. Arsenite of silver, though not quite so deep a yellow. 



CATECHISM ON CHEMISTRY. ]11 



CARBONATES. 



Q,. Are carbonates of native or artificial origin ? 

A. Both. Those of the alkalies and alkaline earths, with 
many others, occur in nature. By double decomposition most 
of them are obtained artificially. 

Q. What property distinguishes carbonates? 

A. Their decomposition with effervescence, owing to the 
escape of carbonic acid ; when subjected to the action of nearly 
all the acids. 

Q. Are they decomposed by heat ? 

A. Excepting the proper alkaline carbonates, heat alone 
expels the carbonic acid, 

Q. Are carbonates soluble ? 

A. The alkaline carbonates are very soluble, the others are 
sparingly so, 

CHROMATES. 

Q. What property distinguishes the chromates ? 

A. Their yellow or red colour. Chromate of lead is found 
in nature. 

Q. What properties distinguish the borates? 

A. Those of the alkalies are soluble in water, all the others 
are sparingly soluble ; they are not decomposed by heat, very 
fusible, and detected when digested in a slight excess of sul- 
phuric acid, evaporated to dryness, and the residue is boiled in 
alcohol, by the solution thus formed, burning with a green 
flame. 

10 DATES AND IDOHYDRATES. 

Q. How may an iodate and idohyrate be obtained ? 

A. By adding iodine to a hot alkaline solution. By the de- 



112 CATECHISM ON CHEMISTRY. 

composition of water, oxygen will convert part of the iodine 
into iodic acid, and hydrogen will form with the remaining 
iodine, idohydric acid, which, by their union with the alkaline 
base, form an iodate and idohydrate. The iodate is insoluble 
in water, while the idohydrate being soluble remains in solution, 

Q. What properties characterize the iodates ? 

A. They form deflagrating mixtures with combustible bo- 
dies, by which they are converted into iodides, are decompo- 
sable by heat, and are all insoluble in water, excepting those of 
the alkalies, which are sparingly so. The strong acids set 
iodine at liberty by depriving iodic acid of its oxygen. 

ARSENIATES. 

Q. Are arseniates of natural or artificial origin ? 

A. Both. The arseniates of lime, nickel, cobalt, iron, cop- 
per and lead, are natural productions. 

Q. Are arseniates soluble? 

A. Excepting those of potash, soda and ammonia, they are 
sparingly soluble in water, but are dissolved in dilute nitric 
acid, and are thrown down again unchanged by ammonia. ' 

Q, Are they decomposed by heat ? 

A. They generally bear a red heat without decomposition, 
but are decomposed b}^ being heated to redness with charcoal. 

Q. How are these salts detected ? 

A. The soluble arseniates are easily distinguished by the 
usual tests for arsenious acid ; and the insoluble arseniates, 
when boiled in a strong solution of the fixed alkaline carbo- 
nates, are deprived of their, acid, and may then be detected in 
"the usual manner. 



SULPHOHYDRA TES. 

Q. What are sulphohydrates ? 

A. Compounds of sulphuretted hydrogen with oxides. 



CATECHISM ON CHEMISTRY. 113 

Q. What properties distinguish tliem ? 

A. The weak affinity between the acid and base, and conse- 
quent decomposition by most other acids, with disengagement 
of sulphuretted hydrogen. They are decomposed also by clilo- 
rine and iodine with separation of sulphur, and formation of a 
muriate, or idohydrate. 

Q. What change do they undergo when their solutions are 
exposed to the air ? 

A. From being colourless or nearly so, they absorb oxygen, 
a portion of its acid is deprived of hydrogen, and a yellow 
coloured sulphuretted sulphohydrate is generated. By con- 
tinued exposure, the whole of the sulphuretted hyrogen is 
decomposed, water and hypo-sulphurous acid being produced. 

Q. What are cyankydrates ? 

A. Compounds of cyanhydric acid with bases, formed by 
the decomposition of water, by means of a cyanide in solution. 

Q. What is an important salt of this class ? 

A. Cyanhydrate of potash. 

Q. Are there any important cya/zo/errifes ? 

A. Yes; cyanoferrite of potash, and cyanoferrite of iron. 

Q. ¥/hat is fulminating mercury ? 

A. It is the cyanate of mercury. 

Q. How obtain it ? 

A. By dissolving mercury in nitric acid, with heat, and 
when cold, add alcohol, then heat until effervescence takes 
place, and when red fumes appear, check the action with water. 
The precipitate well washed with water, and afterwards dried 
at a gentle heat, will be the cyanate of mercury. 

Q. Is chlorine capable of uniting with metallic oxide ? 

A. Yes; by the action of chlorine on lime, chloride of lime 
is formed. 

END OF INORGANIC CHEMISTRY. 



10* 



114 CATECHISM ON CHEMISTRY. 



ORGANIC CHEMISTRY. 

d. What do organic wsubstances comprise ? 

A. All those that are created in vegetables and animals,—. 
all such as are generated from these, by spontaneous action or 
otherwise, and such as arise from the reaction of either of the 
above, with inorganic bodies. 

CI. Why is a knowledge of organic chemistry of less difficult 
acquirement than that of the chemistry of inorganic substances? 

A. Because the ultimate elements are fewer in number and 
peculiarly well known. 

Q. What are characteristics of organic substances ? 

A. They are composed of the same elements, very prone to 
spontaneous decomposition, it is impossible to form them by 
art, and are decomposible by heat. 

Q. How is organic chemistry divided ? 

A. Into Vegetable and Animal Chemistry. 

VEGETABLE SUBSTANCES. 

Q,. What are the ultimate elements of vegetable substances ? 

A. Hydrogen, oxygen and carbon, variously combined so as 
to display the most opposite properties. 

Gl. Do any other elements ever enter into the composition of 
vegetable substances 1 

A. Yes. Some of the alkalies and alkaline earths, with 
minute portion of iron exist in them. The vegetable alkalies 
contain nitrogen. According to Lieblg, nitrogen is always to 
be found in vegetable organs, though not in their products, and 
that it is indispensable to the thriving of the plant. 

Gt. Are hydrogen, oxygen and carbon uniformly present in 
vegetable matter ? 

A. No. In some essential oils, in caoutchouc, in ammonia, 



CATECHISM ON CHEMISTRY. 115 

in cyanogen and in some compounds derived from these sub- 
stances, there is no oxygen ; while in oxalic acid and in some 
other oxides of carbon, no hydrogen exists, but in no instance, 
excepting that of ammonia and its supposed associates, amide 
and ammonium, is carbon deficient. 

d. What may we consider the composition of those vegeta- 
ble substances to be in which the hydrogen and oxygen exist 
in the exact proportion for forming water? 

A. Compounds of water and carbon, or, according to Prout, 
hydrates of carbon. Examples of these are furnished by such 
vegetable substances, that are neither acid, oily nor resinous, 
as for instance, gum, sugar, starch, lignin, &c. 

Q. What results when vegetable substances, devoid of nitro- 
gen, are subjected to distillation ? 

A. They first yield the water and essential oils existing in 
them ; then, as the heat is increased, certain essential oils or 
spirits analogous to alcohol, are sometimes evolved, and at the 
same time, or subsequently, acetic acid and bituminous matter 
mixed, and carbonic oxide, carbonic acid, and carburelted hy- 
drogen are generated; and by further ignition these products 
are converted into carbonic oxide and carburetted hydrogen 
with a deposition of carbon. 

Q. What results when vegetable substances containing ni- 
trogen are subjected to distillation ? 

A. Ammonia, or cyanogen, or some of these compounds are 
generated, in consequence of the union of an atom of nitrogen 
with the carbon or hydrogen present. 

Q,. What results when wood is subjected to heat and pres- 
sure? 

A. A bitumen, analogous to mineral coa]» 
Gl. What results when vegetable substances are heated in 
the air? 

A. Water and carbonic acid only. 

Gl. How may the ultimate analysis of organic substances be 
effected ? 



liG catelhism on chemistry. 

A- By heating the substance with oxide of copper, so as to 
oxidize all the carbon and hydrogen present, and liberate the 
nitrogen if there be any. We estimate the quantity of hydro- 
gen by the amount of water produced, and the carbon by the 
amount of carbonic acid. See Hare, p. 374. 

Gl. How are the elements of organic bodies associated or 
grouped ? 

A. Into simple or ultimate elements; and into proximate or 
compound elements. The latter is capable of acting as a sim- 
ple element, and is called by Liebig Compound Radicals. 

QL' How may we exemplify this distinction ? 

A. Oxalic acid may be regarded as a compound of carbonic 
oxide and carbonic acid, acting as compound elements or radi- 
cals, or as composed of carbon and oxygen in certain propor- 
tions, acting as simple elements. The carbon and oxygen are 
the ultimate; and the carbonic oxide and carbonic acid, the 
proximate elements in this case. 

Q,. Can you enutnerate some of the most important com' 
pound radicals ? 

A. Yes. Amide ^carbonic oxide, ethyl^ acetyl^ methyl^ f or myl, 
amyl, Sfc. ' ^ 

Gt. What can be said of amide ? 

A. That it is the compound radical in ammonia, which may 
be considered as an amiduret of hydrogen, formed when we 
substract one atom of hydrogen from ammonia, consisting of 
Ni H2 * 

Q,. How is this substance demonstrated? 

A. By heating potassium in ammonia, the former is con- 
verted into an olive coloured mass which, by contact with water, 
is converted into potash and ammonia. 

Gl. What is the rationale ? 

* Initials. O for oxygen ; H for hydrogen ; N for nitrogen ; C for carbon. 
The figures represent the number of equivalents or atoms of each, as Ol 
one atom of oxygen, H2 two atoms of hydrogen. 



CATECHISM OiN CHEMISTRY. 117 

A. The potassium takes the amide from the ammonia form- 
ing- an amiduret of potassium ; which, when presented to the 
water, an additional atom of hydrogen is supplied to the amide 
thus regenerating ammonia, and also an atom of oxygen to the 
potassium to form potash/ 

Q.. What are oxamide and carbamide ? 

A. The former is a compound of carbonic oxide and amide, 
the latter or carbamide is formed by the union of carbonic acid 
with a?nide, 

CI. What can be said of Benzule? 

A. It is the compound radical, inferred to exist in 'benzoic 
acid and in the essential oil of bitter almonds. Composition 
C4 H5 and 02. 

Gl. What is Cinnamyle? 

A. It is the radical found in the pure oil of cinnamon. Com- 
position CIS, H8, 02. 

a. What is Salicyl ? 

A. It is the hypothetical radical in the oil of spirea ulmaria, 
queen of the meadow, and is evolved from a substance called 
salicin, which is extracted from the leaves and bark of the 
willow and from some species of poplar ; it is an oily inflam- 
mable liquid. Composition C'^, H^, O^. 

Q. What is Ethyl ? ' 

A. It is regarded as the compound radical, existing in alco- 
hoi and in ether, ether being regarded as the oxide of ethel and 
alcohol the hydrated oxide of elhel. 

Ql. What is the composition of ethyl 7 

A. It consists of carbon and hydrogen represented by the 
formula C4 FR 

Gt. In what respect does etherine differ from ethyl in its 
composition 7 

A. In containing on atom less of hydrogen, and is repre- 
sented by the formula tF C^, that is, one equivalent. Accord- 
» ing to Liebig we may consider etherine isomeric with defiant 
gas. 



1 J S CATECHISM ON CHEMISTRY. 

Q. What is the proximate and ultimate analysis of alcohol 
and ether 1 

A. Alcohul may be considered as composed of etherine and 
water in equal volumes, or in atoms one of etherin to two of 
water. Ether differs from alcohol in containing an atom less 
of water or half the volume in proportion. The ultimate 
elements of these are represented thus : the formula for ether 
C4 W 01, for alcohol C4 H^ 02, or C^ Rs Qi. Thus if we take 
an atom of water from alcohol we have ether. 

Q. How may the etherial compounds of ethyl be classified? 
A. Into simple ethers, formed by the union of ethyl with 
any basacigen element, and which may be named after such 
element as the oxide, chloride or bromide of ethyl, and into 
the compound ethers, which is formed by the union of an 
acid, with any of these. 

Q,. Can you describe the properties of ethyH 
A. No. It has never been isolated. 
d. What is acetyl ? 

A. It is the radical existing in acetic acid, and plays the 
same part in a newly discovered liquid, called aldehyde, that 
ethyl does in alcohoh Composition C^ H^. 
Q,. What can be said oi'mesityl? 

A. It is a colourless inflammable liquid, existing in acetone 
which is inferred to be a hydrated oxide of mesityl. 
Q. How is acetone obtained ? 

A. By passing the vapour of pure acetic acid through a red 
hot porcelain tube, the acid is decomposed, and the product, 
which is a colourless liquid, is the acetone. 
Q,. How is mesityl obtained from acetone '? 
A. By distilling acetone, with half its volume of fuming 
sulphuric acid, and washing the oil with w^ater. Composition 
of mesityl is C^, H^. 

Gl. What can be said ofkacodyl? 

A. It is an etherial limpid, liquid, spontaneously inflamma- . 
ble, sinking in water without dissolving, but soluble in alcohol 



CATECHISM ON CHEMISTRY. 119 

and ether, and containing an atom of arsenic, Composition C^, 

Gl. Wiiat is said of methyl ? 

A. It is the radical in pyroxilic acid, which is obtained by 
the destructive distillation of wood, also called wood spirit. 
Composition C2, Hs. 

Gl. What is said of for myl, amyl, glyceryl^ and cetyl ? 

A. Formyl is said to bear the same relation to methyl, that 
acetyl does to ethyl. Amyl is a peculiar liquid noticed by 
Scheele"to accompany potato spirit ; glyceryl is considered as 
the base of a number of fixed oils, while cetyl performs a simi- 
lar part in spermaceti. 

NUTRITIOUS VEGETABLE SUBSTANCES DE- 
VOID OF NITROGEN. 

Q,. Enumerate some of the substances of this class ? 

A. Gum, sugar, starch and lignin. 

Q. What are the characteristic properties of gum ? 

A. It is neither sweet nor sour, generally soluble in water, 
insoluble in alcohol and in ether, and not coagulable by heat. 

Gt. How are gums divided ? 

A. Into three classes, namely : 1. Arabin^ which is soluble 
in cold water; exemplified by gum arabic. 2. Bassorin^ which 
swells into a jelly, but does not dissolve in water ; exemplified 
by gum bassora, or tragacanth. 3. Cerasin^ which is insoluble 
in cold, but soluble in boiling water, and yields less mucic 
acid than bassoria when treated with nitric acid. The gums 
of the cherry, apricot, peach and almond, exemplify the 3d 
class. 

Gt. Which is the most perfect specimen of pure gum ? 

A. Gum arabic, composed of C^, H^, O^. 

Gt. What are tests of gum arabic *? 

A. Alcohol, which precipitates it from solution, and with 
the sesquioxide of iron, it yields a yellow precipitate after some 



120 CATECHISM ON CH.^MISTRY. 

hours. This gum also precipitates the protoxide of mercury 
from the nitrate. 

Gl. What are the two forms in which sngar occurs ? 

A. Crysiallizable sugars, as sugar candy, dicC, and the un- 
cry stalliz able ^ as molasses, honey, &c. 

Q.. What are the properties of sugar? 

A. It has a sweet taste, soluble in its own weight of water, 
also soluble in alcohol. It unites with alkalies and alkaline 
earths, and with the oxide of lead forming compounds. It also 
decomposes some salts, reviving the metal. Its most striking 
property is its capability of undergoing the vinous fermenta- 
tion, by which it is converted into alcohol. 

Gl. What effect has sulphuric and nitric acid on sugar ? 

A. By the former it is decomposed with depositions of car- 
bon ; by the latter, it is converted into oxalic acid. 

Q,. What is sugar an antidote for ? 

A. Acetate of copper, in which it acts hy removing a por- 
tion of oxygen. 

CI. What is considered the atomic constitution of sugar? 

A. One equivalent of water, to on^ equivalent of carbon ; or 
of oxygen, hydrogen and carbon, each one atom. 

Gt. What are the different kinds of sugar 1 

A. Cane sugar, grape sugar, lactin or sugar of milk, mush- 
room sugar, liquorice sugar, manna sugar or mannite, &c. 

Q.. In what respect do these sugars differ ? 

A. Grape sugar is distinguished, by being very slightly ope- 
rated upon by mineral acids; the sugar of milk by being in- 
soluble in alcohol or in ether ; mushroom sugar by not precipi- 
tating the oxide of copper from a boiling solution of the acetate ; 
and liquorice sugar by forming sparingly, soluble compounds 
with the mineral and vegetable acids. 

d. What is starch or fecula ? 

A. It is a peculiar substance obtained from the meal, or 
flour of grain, and from the tubers of the potato, and various 



CATECHISM ON CIIEMJSTIIY. 121 

other vegetables, round in commerce under the names of sago, 
tapioca, arrow-root, &c. 

Q. What discovery was made by Leeuwenhoeck, and con- 
firmed by subsequent microscopic observations '? 

A. That starch consists of globular grains, each enveloped in 
a tegument, differing from the internal mass. Raspail found 
the interior portion was soluble, and the sac insoluble in water 
and that these globules vary in size in the different plant whence 
it is derived. 

d. What are the characteristic properties of fecula or 
starch ? • 

A. It is white, insipid, inodorous, insoluble in alcohol, ether 
and cold water, soluble in a large quantity of boiling water, from 
which it is precipitated by acetate of lead, and its best test is 
iodine, with which it forms a blue iodide of starch. Starch 
forms soluble salts with alkalies, from which it is precipitated 
by acids. Dilute acids convert it first into gum, and then 
sugar, and when heated with nitric acid, it is converted into 
•oxalic acid. 

Gt. What is diastase 1 

A. It is the sugar producing principle, existing in malt, in 
the proportion of ^ ^ ^ obtained in the form of a white solid amor- 
phous substance, soluble in water, and in weak alcohol, but in- 
soluble in absolute alcohol. 

Gt. What is dextrine ? 

A. It is a peculiar sweetish substance made by the digestion 
of starch with malt, and which, by a species of fermentation, is 
converted into grape sugar. 

Q.. What is lignin? 

A. It is the fibres of wood, and the most abundant proximate 
principle in vegetables, obtained by treating the sawings of 
wood, &c., successively with ether, alcohol, water, diluted acid, 
and a caustic alkaline solution, so as to remove all the soluble, 
matter. 

Gl. What are the properties of lignin ? 
11 



122 CATECHISM ON CHEMISTRY. 

A. It is tasteless, inodorous, insoluble, and yields by boiling 
sulphuric acid upon it, gum and grape sugar; and by nitric acid, 
it yields malic, oxalic, and acetic acids. 

d. Enumerate the substances designated vegeto-animal? 

A. Gluten, vegetable albumen, vegetable fibrin, and legumen, 
or vegetable caseine. 

a. What is gluten ? 

A. It is the gray, viscid substance that remains after washing 
away starch from flour, existing also in the seed of the grape, 
and in leguminous plants, &:c. 

Q,. What properties distinguish gluten ? 

A. It is yellow and translucent when dry, gluey when moist, 
insoluble in water or ether, but readily soluble in boiling alco- 
hol, and in dilute acid solutions. 

Gl. What is vegetable alhiimen? 

A. It is found in combination with gluten in the seeds of 
grapes, and in almonds, and also in the seeds of the ricinus in 
union with an oil, and in all vegetable juices which coagulate 
wnth heat. 

Q,. What properties characterize vegetable albumen? 

A. It is soluble in water, insoluble in alcohol, not adhesive, 
becomes opaque by drying, and soluble in caustic alkaline 
solutions, from which it may be precipitated by acids, by ferro- 
prussiate of potash, chloride of mercury, and infusion of galls. 

Gl. What do we understand by the vegetable Jibrine of 
Liebig? 

A. That portion of wheat flour that is not taken up by boiling 
alcohol, from the glutinous mass mechanically obtained by 
washing wheat dough in a bag, 

Gl. W^hat properties distinguish vegetable fibrin from gluten 
and vegetable albumen? 

A. From the former it diflTers in not being soluble in alcohol, 
or glutinous, from the latter in not being soluble in water, nor 
coaguldble by heat. 

Q. What is said of legumen or vegetable caseine ? 



CATECHISM ON CHEMISTRY. 123 

A. It is a substance interniediate between gluten and vegetable 
albumen, not being coagulable by heat like the one, nor like the 
other soluble in alcohol, while insoluble in water. 

OF OILS. 

d. What properties characterize oils ? 

A. They have a peculiar unctous feel, are inflammable, and 
insoluble in water, 

d. How are oils divided ? 

A. Into fixed and volatile. 

Q,. What properties distinguish the fixed oils ? 

A. They are nearly insipid and inodorous, are lighter than 
water, decomposed by distillation into a volatile oil and carbu- 
retted hydrogen ; soluble in ether, sparingly soluble in alcohol, 
Vv'hen heated in the air take fire, producing water and carbonic 
acid, capable of forming soaps with alkalies, and above all are 
distinguished from the. volatile oils in remaining fixed when 
exposed to the air^ and not being vapourized at the boiling point 
of water, when subjected to the distillatory process with that 
liquid. 

Gt. What are the proximate constituents of the fixed oils? 

A. They are oZeiw, stearine, and margarine. Olein is the 
more fluid, while stearine and margarine constitute the less 
fluid ingredient of the fixed oils. 

Gl. How may we isolate these pro^mate constituents ? 

A, By first dissolving the fat or oil in boiling alcohol, and 
allowing it to cool when the stearine and margarine are 
separated by congelation. Then subject the congealed mass 
to ether with as much heat as it will bear without boiling. 
The margarine is taken up by the ether in which it is soluble, 
leaving the stearine behind, undissolved. Lastly, by distillation, 
the alcohol may be removed from the olein^ and the ether from 
the margarine. 

Q,. What properties distinguish olein? 



124 CATECHISM ON CHExMISTRY. 

A. It is the fluid part of oils, is soluble in hot or cold alcohol 
and remains liquid at zero. 

Q.. What properties distinguish stearine ? 

A. It is a white crystalline solid, not greasy to the touch, 
easily pulverized, soluble in boiling alcohol., but insoluble in 
cold alcohol, water, or ether. 

Q,. What properties characterize margarine ? 

A. It is a white crystalline solid, more fusible than stearine, 
and is soluble in alcohol and ether. 

Ct. What is the composition of olein, stearine and margarine? 

A. Olein consists of 1 atom of oxide of glyceryl, two of oleic 
acid and two of water. Stearine differs from the last in sub- 
stituting two atoms of stearic for the oleic acid and margarine, 
in containing, in place of either, two atoms of margaric acid, 
and in containing only 1 atom of water. 

Q.. Do the different kinds of oils contain any other proximate 
constituents ? 

Gl. Yes : viz. spermaceti found in the crania of the cachalot 
whales, delphinine in the oil of the dolphin, butyrin, caproin, 
and caprin in butter, ricin in the ricinus communis, crotonine 
in the oil of the crotontiglium, (fee. 

d. In what respect do the summer and the winter strained 
oils of commerce differ? 

A. The one contains a large portion of olein, with a small 
proportion of stearine, the other contains a greater proportion of 
the latter and less of the former ; hence the one is prepared by 
straining at a lower temperature than the other. 

Gt. What chemical change does saponification consist in ? 

A. When the oils or fats are boiled with an alkaline oxide, 
the oxide of glyceryl is dispossessed of its acid by the superior 
affinity existing between the latter and the alkali. The acid 
thus transferred is named according to the substances by which 
it is respectively yielded. Thus we have oleic, stearic and 
margaric acids. 

d. What properties distinguish the volatile oils ? 



GATEGHISM ON CHEMISTRY, 125 

A. They have a penetrating smell, an acrid taste, more solu- 
ble in alcohol and more inflammable than fixed oiL-, are suscep- 
tible of spontaneous evaporation, can be distilled with boiling 
water without decomposition ; they are incapable of forming 
soap with alkalies, and maybe evaporated from a surface with- 
out leaving a stain, 

Q.. What are the proximate constituents of volatile oils? 

Gl. They consist of a more fluid and a less fluid oil. The 
former of these has been called elaopten or okesBence, the latter 
stearopten or steuressence. 

d. Can you enumerate some of the most important volatile 
or essential oils ? 

A. Yes. Oil of turpentine, kreosote, cajcput, fennel, pepper- 
mint and camphor, &:c. 

d. Do any of the volatile oils contain sulphur ? 

A. Yes. The volatile oils of black mustard seed, of horse- 
radish, of onions, &c. 

Gl. Are there any volatile oils devoid of oxygen? 

A. Yes. The oils of turpentine, bergamotte, juniper, citron, 
copaiva, parsley, savine, cubebs and black pepper are of this 
description. 

Gl. What is said of the oil of turpentine 1 

A» It is the cheapest and most used of the essential oils, 
colourless and limpid when pure, having the formula of C^o H'^. 

Gl. What is camphor'? 

A. It is a concrete volatile oil, represented as the stearopten 
of the oil of camphor. By distilLition with anhydrous phos- 
phoric acid, it results in a colourless liquid called camphogen; 
it is a hydruret of carbon, having the formula C^o H^ O'. 

Q. What is artificial camphor'? 

A. It is a white crystalline subvstance resembling camphor in 
odour and volatility, obtained by saturating oil of turpentine with 
chlorohydric acid gas. 

Q. What is obtained by distilling artificial camphor with 
quicklime ? 

11* 



126 CATECHISM ON CHEMISTRY. 

A. An oil, identical in composition with pure oil of turpen- 
tine, known by the name of camphene or camphelene. 

CI. What is kreosote ? 

A. It is an essential oil, being a product of the destructive 
distillation of vegetable matter. 

Gl. What are the properties of kreosote 1 

A. It is an oleaginous, colourless and transparent liqaid, 
having the odour of crude pyroligneous acid, or of smoked 
meat, a burning caustic taste, a sense of greasiness to the touch, 
rather heavier than water, with which it forms two combinations, 
tiie one a solution of one part of kreosote to four hundred of 
water, the other a solution of one part of water to ten of kreosote ; 
it unites in all proportions with alcohol, ether and naptha, and 
is a solvent of iodine, phosphorus and sulphur. The formula 
of composition C^^ H^ 02. 

Q. What are resins ? 

A. They are concrete insipissated juices which exude from 
certain plants in union with essential oils, of which common 
resin or rosin is an exemplification. 

Q. What properties characterize the resins 1 

A. They are solid, brittle when pure, inflammable, suscepti- 
ble to a small extent of saponification; they cannot be distilled 
without decomposition ; insoluble in water, but are soluble in 
alcohol, ether, the fixed and volatile oils, in acetic acid, and in 
chlorohydric acid. They are decomposed by sulphuric acid, 
and by reaction with nitric acid are explosive. 

d. W^hat is wax ? 

A. It is a kind of concrete fixed oil, obtained from certain 
plants of which bees make their honeycomb, &c. 

Q. What are the properties of wax ? ' 

A. Pure white wax is insipid, inodorous, insoluble in water, 
partly soluble in boiling alcohol, and perfectly soluble in essen- 
tial and fixed oils, is susceptible of saponification, and yields 
oleic, stearic and margaric acids and also glycerine. 



CATECHISM ON CHEMISTRY. 127 

Q,. Does animal wax (bees-wax) differ in any respect from 
vegetable wax ? 

A. Yes. In being susceptible of only a partial saponifica- 
tion, and in being found to consist of a substance called myri- 
cine, which is insoluble in boiling alcohol, and of a substance 
called cerine, which is soluble in boiling alcohol. 

Q. What is caoutchouc ? 

A. It is the concrete juice of certain plants, which is con- 
gealed in moulds and consists of C^ H^. 

Gt. What are the striking properties of gum elastic 7 

A. It is an elastic, tenacious gum, insoluble in water, alcohol 
and cold acids, but slowly soluble in ether and the volatile 
oils. The oil cajeput is a good solvent. Dr. Mitchell has dis- 
covered that the oil of sassafras, after the operation of ether, 
is a good solvent. 

Ct. What are balsams? 

A. They are native solutions of resinous matter in essential 
oils which exude spontaneously from trees and shrubs. 

Q.. What are gum resins ? 

A. These are a class of vegetable substances, consisting of a 
mixture of resin, gum, essential oil, and extractive matter. 

Gt. What substances are designated as gum resins ? 

A. Opium, aloes, ammonia, assafcetida, euphorbium, galba- 
num, gamboge, myrrh and scammony. 

Gl. What is the best solvent for gum resins ? 

A. Proof spirit, (which is alcohol and water,) because, the 
resin and essential oil require alcohol, and the gum and ex- 
tractive matter, water, for solution. 

Gl. What is the nature of the substances bitumen, petroleum, 
naptha, amber ? 

A. They exist in nature ready formed, are very inflammable, 
consisting in general of hydrogen and carbon, presenting a 
series of substances from the most volatile as naptha, to the 
most dense, as anthracite coal. 



128 CATECHISM ON CHEMISTRY. 



OF ACIDS. 



Q,. Do all vegetable acids exist isolated or free from union 
with a base? 

A. No. For when water or any other oxide cannot be expelled 
from an acid without the decomposition of the acid, such water 
must be considered as acting as a base, hence called basic. 

Gt. How may acids be divided ? 

A. Into monobasic, bibasic or tribasic, according to the 
quantity of base with which they are capable of combining. 

Gt. Can you enumerate some of the vegetable acids ? 

A. Yes. These are the acetic, tartaric, citric, malic, me- 
ccnic, kinic, galHc, benzoic, &c. 

Gl. What vegetable acid is most abundant in nature ? 

A. Acetic. It exists in the sap of almost all the plants and 
in many of the animal secretions, and is the product of the 
destructive distillation of vegetables. Vinegar is a dilute acetic 
acid. 

Q,. How is acetic acid obtained ? 

A. By distilling any of the acetates with sulphuric acid and 
then re-distilling. 

Gl. What conditions are required for acetous fermentation? 

A. The presence of water, yeast and alcohol, in some form; 
at a temperature between 60 and 80 degrees. 

Gt. What does the process consist in ? 

A. The conversion of alcohol into acetic acid. The rationale 
is explained by the formation of carbonic acid and water, in 
consequence of the union of the oxygen of the air with the 
carbon and hydrogen of the alcohol, which escape, leaving hy- 
drogen, carbon and oxygen in proper proportions for forming 
acetic acid. 

Gl. What are the properties of acetic acid ? 

A. It is a very sour, pungent liquid, very volatile and vola- 
tilizes without entire decomposition, crystallizes at low tern- 



CATECHISM ON CHEMIgTRY. 129 

peratures, produces, while fumes on contact with the aqueous 
vapour of the atmosphere, it boils at 142 degrees, and unites in 
all proportions with water, alcohol, ether, many essential oils, 
camphor and some resins ; and its vapour burns with a blue 
flame, which results in water and carbonic acid. Formula O^ 

H3 03. 

Gl. What is pyroligneovs acid ? 

A. It may be considered as the matter of wood smoke in 
the liquid form. It is generated when charcoal is obtained 
from wood. It contains beside acetic acid, paraffine, eupione, 
kreosote and pyretene. 

Gl. Where does lactic acid exist? 

A. In sour milk, and is a product of a peculiar fermentation 
called viscous, to which the juices of plants containing albumen 
are spontaneously liable when yeast is not added. 

Gt. Wlmi is citric acid? 

A. It is a crystalline substance existing in limes and lemons 
in union with mucilage and malic acid. Its formula is repre- 
sented by C'2 m OH. 

Q. What is malic acid ? 

A. It is the acid which predominates in the apple as well as 
in gooseberries and currants. 

Gl. Where does tartaric acid ex\sil 

A. In many vegetable substances, and is a deposit from 
wine in the form of bitartrate of potash (cream of tartar.) 

Q. How is it obtained ? 

A. By saturating the excess of tartaric acid in cream of tar- 
tar with chalk, and decomposing the precipitate with dilute 
sulphuric acid. 

Gl. What are the properties of tartaric aeid ? 

A. It has a very sour taste, reddens litmus, soluble in water 
and alcohol; and distinguished from other acids by forming a 
white precipitate with the salts of potash. It possesses the sin- 
gular property of uniting with two bases at once, forming what 
are called triple compounds. With oxide of antimony it forms 



130 



CATECHISM ON CHEMISTRY. 



tartar emetic, and with carbonate of soda Rocbelle salt. Tar- 
taric acid is bibasic, its formula represented by C^ H^ O'O. 
Ct. What is paratartaric or racemic acid ? 
A. A peculiar acid, identical in composition with tartaric 
acid, formed in preparing the latter, but differs from it in that 
it crystallizes in a different form, and is less soluble. 

Q.- Where does tannic acid exist ? 

A. It exists in a great number of vegetables, (generally in 
the bark and root,) and is peculiarly abundant in nut galls. It 
is the most general astringent principle in vegetable products. 

Q.. What are its properties ? 

A. It is of a yellowish white colour, inodorous, of an astring- 
ent taste, somewhat crystalline, soluble in water, ether, and 
by the aid of heat in alcohol. It is precipitated by alkalies, 
lime water, and muriate of tin. Its most peculiar property is 
its reaction with a salt of iron and with gelatin, producing with 
the former a black compound, with the latter, a yellowish fioc- 
culent precipitate. 

Q,, What is a good antidote for the poisoning from tartar 
emetic ? 

A. An infusion of galls or of oak bark, on account of the 
insolubility of the tannate of antimony which would be formed. 
Tanic acid is tribasic; its formula is C^s H^ 09. 

Q,. Where does gallic acid exist ? 

A. In the bark of trees, and united with tannic acid in nut 
galls. 

Q. What are the properties of gallic acid ? 

A. It crystallizes from a hot solution in thin silky needles 
which require 100 parts of cold water for solution, although 
when boiling, 3 parts are sufHcient. It is very soluble in alco- 
hol and sparingly soluble in ether. It is a monobasic compound 
represented by the formula C7 HO^. 

Q,. In what does meconic acid exist? 

A. In opium, combined with morphia and codeia. 

Q,. How is it obtained ? 



" CATECHISM ON CHEMISTRY. 131 

A. By adding a solution of acetate of lead to an infusion of 
opium, we have a precipitate of meconate of lead. Then by 
means of sulphydric acid, the lead may be separated as a 
sulphide, and the meconic acid being liberated, can be obtained 
by filtration. 

Q,. What are the properties of meconic acid ? 

A. It is a crystalline solid, having at first a sour, and subse- 
quently a bitter taste, soluble in water and alcohol, produces an 
intense red coloured precipitate with the sesquioxide of iron, 
and an insoluble precipitate with protoxide of lead. Meconic 
acid is tribasic; its formula is represented by C^^ HOi^+HO^* 

d. What is used as a test for opium ?^ 

A. Iron, as meconic acid exists only in that drug. 

d. What is formic acid ? 

A. It is an acid which appears to exist naturally in ants, 
having a pungent taste and a peculiar sharp odour. 

Ct. Where is kinic acid'? 

A. It exists in Peruvian bark with quinine and cinchonia. 

Q. What is benzoic acid? 

A. It is a concrete volatile oil, existing in gum benzoin. 

Q,. Where is succinic acid 1 

A. It exists, ready formed in amber. 

Q. Where is hippuric acid ? 

A. It is found in the urine of herbivorous mammalia. 

Q,. What is sulpho-vinic acid ? 

A. It is a double sulphate of the oxide of ethyl and water, 
consisting of two proportions of the acid, one of the oxide, and 
one of water, obtained either by heating at 280^ equal weights 
of concentrated sulphuric acid and alcohol ; or by saturating 
sulphuric acid with the vapour of ether, and adding water after 
some hours, and then in either case saturate the resulting 
liquid with oxide of lead, with lime, or boryta. From the re- 
sulting sulpho-vinates the acid may be obtained by adding 
enough acid to saturate the inorganic base. 



132 CATECHISM ON ClIE^lISTRY. 

Q,. Where does uric acid exist ? 

A. It is an ingredient in the urine, and the most abundant 
material in urinary calculi. 

Q. What are the properties of this acid ? 

A. It crystallizes in thia spangles, with a dazzling white 
saline lustre. It is insipid, inodorous, heavier than water, almost 
insoluble in cold and but little soluble in boiling w^ater. It is 
soluble in dilute nitric acid with effervescence, from the escape 
of nitrogen and carbonic acid. 

Gl. W^hat does the resulting solution contain 1 

A. Alloxan^ alloxatin, urea, par ahanic acid and ammonia. 

Q.. By what means^can we recognize this acid ? 

A. By adding to the above solution in nitric acid an excess 
of ammonia, the concentrated liquid becomes of a purple red, 
on account of the generation of murexide. 

OF ORGANIC OR VEGETABLE ALKALIES. 

Gt. W^hich are the most important of these ? 

A. Morphia, quinina and cinchonia. Besides these we have 
codeia, narcotina, strychnia, ametia, atropia, &c. 

Ql. What properties are common to the vegetable alkalies? 

A. They are solid, white, inodorous and of a bitter and acrid 
taste; they render the syrup of violets green, and are all soluble 
in alcohol, and nearly or quite insoluble in cold water. 

Gl. How are these alkalies generally obtained? 

A. They are separated from the acids with which they are 
combined as they exist in nature, by precipitation from a solu- 
tion containing them, by means of a more salifiable base, such 
as potash, soda, ammonia, lime, or magnesia. Purified by mix- 
ing with animal charcoal and dissolving in boiling water. 

Q. What are the ultimate constituents of vegetable alkalies'? 

A. Oxygen, hydrogen, carbon, and nitrogen. They yield 
ammonia by destructive distillation. 

Q., Where is morphia found ? 

A. It is the most important active principle in opium, and 



CATECHISM ON CHEMISTRY. 133 

exists in chemical union with meconic acid only, but is me- 
chanically associated with various substances. 

0.= How is morphia obtained "l 

A. By adding to laudanum liquid ammonia, the morphia 
precipitates. 

Qi What properties distinguish morphia'? 

A. It crystalHzes in rhombic prisms, has an enduring bitter 
taste, produces a fine red colour with nitric acid, and a solution 
thus reddened is precipitated, of a dull brown colour, by proto- 
muriate of tin. Morphia may be distinguished by decomposing 
iodic acid. Subjected to chlorine in water, it becomes orange- 
red and then dissolves. The salts of morphia are crystallizable 
and soluble in water. 

Q,. What is paramorpkia and pseudomorphia ? 

A. They are newly-discovered substances found in opium, 
identical in composition with morphia. 

Q,. What properties distinguish them 1 

A. Paramorpkia also called tliebain has an acrid and styptic 
taste, and differs from morphia in not forming crystallizable 
salts with acids, and not striking a blue colour with the salts of 
iron; and also in producing tetanic symptom^ upon the system 
when given in doses of a grain. Pseudomorphia differs from 
morphia in not being poisonous. 

Q.. What is codeia or codeine '? 

A. It is an alkali existing in opium as a meconate, differing 
from morphia, by the form of its crystals, by its greater solu- 
bility in water, and by its insolubility in alkaline solutions. 

Gl. What is narcotina or narcotine '? 

A. It is an alkali existing in opium, of a crystalline struc- 
ture, and having the property of being soiled by caoutchouc, 
resin, and colouring matter. 

Q. How is it obtained ? 

A. By treating opium with ether near the boiling point of 
that liquid for several days, then decanting and evaporating, the 
narcotine will appear in slender prismatic crystals. 
12 



134 CATECHISxM ON CHEMISTRY. 

Q. What is narceia or narceine ? 

A. It is an alkaline principle existing in opium. It is in 
white silky, acicular crystals, inodorous, of a slightly bitter 
taste, sparingly soluble in water, more soluble in alcohol, and 
insoluble in ether. It does not, like morphia, become blue with 
the salts of iron, nor red with nitric acid. 

Q,. Where does quinia exist? 

A. In Peruvian bark, in union with kinic acid, as a kinate 
of quinia and cinchonia. 

Gt. How is quinia or quinine obtained? 

A. It is generally procured from yellow bark. This is to be 
coarsely powdered, and then boiled in water with a little sul- 
phuric or chlorohydric acid. The bark is to be subjected to 
subsequent boilings, with half, and one-fourth part of the acid, 
at first employed successively, until all the soluble matter is 
extracted; then saturate the acid in the united solutions with 
hydrate of lime, afterwards boil in alcohol, and- lastly, distil off 
the latter. 

Q, What are the properties of quinia ? 

A. It is intensely bitter, its crystals are needle shaped, but 
difficult to form ; it requires for solution two hundred parts of 
hot water, and is almost insoluble in cold water ; its salts are 
soluble, but its sulphate is less soluble than the sulphate of 
cinchonia. 

Gl. What are some of the salts of quinia ? 

A. The chlorohydrate or muriate, the phosphate, the cyano- 
ferrite or ferroprussiate, and the most important is the sulphate 
of quinine. 

Gl. With what has the sulphate of quinine of commerce been 
adulterated ? 

A. Boric acid, sulphate of lime, margaric acid and sugar. 
By subjecting the mass to a red heat and dissipating the sulphate, 
the adulterations may be exposed. The margaric acid may be 
detected by its insolubility in diluted acids, the sugar by the 
sweet taste, perceptible when the quinine is precipitated by 
means of carbonate of soda. 



CATECHISxM ON CHEMISTRY. 135 

CI. What is cinchonia or cinchonine ? 

A. It is an alkali existing in gray bark, obtained by the 
same means that quinia is from the yellow bark. 

Gt. What are the peculiar properties of cinchonia 1 

A. It has a peculiar bitter taste, is white, crystallizable, and 
distinguished from quinia in its acetate being uncrystallizable. 

Gl. What is aricina or aricine ? 

A. It is a white, transparent, crj^stalline substance found in 
a bark brought from Arica, Nitric acid makes it green, and it 
is completely insoluble in water. 

Q,. What is strychnia or strychnine ? 

A. It is a poisonous principle existing in the strychnos nux 
vomica. 

Gl. What are its properties 1 

A. It is crystalline, white, having an intolerably bitter taste, 
leaving a metallic impression in the mouth. It is nearly solu- 
ble in water or ether, but very soluble in alcohol. It is a terri- 
ble poison. 

Gl. What is hrucia or brucine ? 

A. It is a peculiar principle found in the bark of the brucia 
antidysenterica, (false angustura). It crystallizes in oblique 
prisms, with parallelograms for their bases ; less bitter than 
strychnia and as a poison, its effects are less violent. 

Gl. What is delphia or delphine ? 

A. It exists in the seeds of the delphinum staphisagria in 
the state of a mallate. It is white, pulverulent, inodorous, with 
an extremely acrid and bitter taste. 

Gt. What is veratria or veratrine ? 

A. It is an alkali obtained from the seed of the verairum, 
sahadilla^ also from the roots of the veratrum album (white 
hellebore), and col^hicum autumnale (meadow saffron). 

Gl. Properties ? 

A. It is white, pulverulent, and inodorous; it is poisonous, 
producing, when inhaled, a dangerous sneezing; its taste is not 
bitter, but excessively acrid. 

a. What is sahadilla ? 



136 CATECHISM ON CHEMISTRY. 

A. It is a white crystallizable substance, insnpportably acrid, 
found accompanying veratria. 

Gl. What isjervina or jer vine ? 

A. It is an alkaline substance found associated with veratria 
in white hellebore. 

Gl. Vv'hat is colchicina or colchicine ? 

A. It is a vegeto-alkali existing in the seeds of the meadow 
saffron. 

Q,. What is emetia or emetine ? 

A. It is a vegetable alkali obtained from ipecacuanha. 

d. What is solania or solanine ? 

A. It is an alkaline substance existing in the black night- 
shade and in the bittersweet, also in the shoots of the potato. 

Gl. What is caffeia or caffein^ called also theine ? 

A. It is the crj^stallized nitrogenated principle found to exist 
both in tea and coffee, being common to both of these substances. 

Gl. What is atropia or atropine ? 

A. It is the alkaline principle procured from a decoction of 
atropa belladonna or deadly nightshade. 

Q,. W^hat is aconitia or aconitine ? 

A. It is a colourless, vitreous, crystalline substance, of a 
sharp, biting taste, intensely poisonous, obtained from the ex- 
pressed juice of the monkhood (aconitum napellus). 

Gl. What is helladonia or beUudonine ? 

A. It is obtained from the belladonna, and consists of colour- 
less, rectangular, prismatic crystals, having an odour resem- 
bling that of ammonia. 

Gl. What is daturia or daturine 1 

A. It is the principle obtained from the datura strammonium. 

Gl. What is conina or coneine? 

A, It is an alkaline principle which exist^in all parts of the 
hemlock, (conium maculatum,) being very poisonous. 

Q. What is picroioxia or picrotoxine ? 

A. It is an extremely poisonous principle existing in the 
coccalus indicus. 



CATECHISM Oi\ CHE]\IiSTRY. 137 

Gl. What is antiaria or antiarien? 

A. It is the active principle of the deadly upas poison. 

Q,. What are some bases obtained from the oil of mustard 1 

A. Thiasinnamina^ obtained by the action of strong ammo- 
nia upon the oil, and purified by distillation ; it is a crystalline 
substance, its formula being C^ H^ N^ S^. Sinnamina, obtained 
from the latter by digesting with moist hydrated protoxide of 
lead till all the sulphur is removed, then subjecting the residue 
first to water, then to alcohol, and evaporating the solution thus 
obtained. The supposed formula being C^ H^ N^. And sina. 
|}oZi««, obtained by depriving the oil of mustard of its sulphur, 
by means of baryta or oxide of lead, having the formula C^^ H12 
N2 02. 

Gt. What is salicine ? 

A. It is a neutral organic principle, existing in the bark 
and leaves of bitter willows and in that of some species of 
poplar. 

OF ETHERS. 

Q,. What are ethers 1 

A. They are peculiar inflammable liquids resulting from the 
decomposition of alcohol. 

Q. How are ethers obtained? 

A. By the action of acids on alcohol. 

Q,. Do the different acids all operate upon the same principle? 

A. No. Sulphuric acid abstracts water from the alcohol, 
cblorohydric acid substitutes a volume of acid vapour for the 
water, while nitric and acetic acid combine with alcohol. 

Gl. What properties characterize the ethers '? 

A. They have a fragrant odour, affecting the animal nerves 

powerfully when inhaled, a stimulating taste, but little soluble 

in water, and highly susceptible of union with alcohol, essential 

oils and resins, are capable of distillation and especially dis- 

12* 



138 CATECHISM ON CHEMISTRY. 

tinguished from alcohol by their very inferior mucibility with 
water. 

Q.. How are ethers divided 1 

A. Into ethylic ethers or those containing ethyl, and into 
methylic ethers, or those containing methyl. 

Q. What are the most important of the ethylic ethers 1 

A. Common ether or oxide of ethyl, nitric or nitrous ether, 
the hyponitrite of the oxide of ethyl. 

Q,. How is the oxide of ethyl obtained 1 ^ 

A. By distilling equal weights of alcohol and sulphuric acid 
together until the appearance of white fumes. 

Gl. What happens if the heat be continued 1 

A. Sulphurous acid and carbon are evolved, and an oily sub- 
stance called etherial oil, or oil of wine passes into the receiver. 

Q. How is the formation of common ether from alcohol ex- 
plained ? 

A. In consequence of the strong affinity of sulphuric acid 
for water, it displaces a portion of the latter from the alcohol, 
so that the remaining elements form ether. For the conversion 
of alcohol into ether requires but the removal of an atom of 
water. 

Gl. What are the properties which distinguish common ether'? 

A. It is a colourless, transparent liquid, having a fragrant 
odour, a pungent, aromatic taste, very inflammable and volatile, 
soluble in alcohol, partly soluble in water, boils at 98 degrees 
of Fahrenheit, and is the proper solvent of volatile oils and 
resins, also of bromine and iodine. The specific gravity is .725, 

Q,. What is etherine ? 

A. It is a compound of hydrogen and carbQn in equal propor- 
tions, and is evolved during the reaction of sulphuric acid with 
alcohol in the formation of the oxide of ethyl (common ether). 

Q. What is the oil of wine ? 

A. It is the active ingredient in Hoffman's Anodyne Liquor, 
being a triple compound of sulphuric acid and the oxide of 
ethyl and of etherine, which comes over in the process of ob- 



CATECHISM ON CHEMISTRY. 139 

taining common ether, mixed with sulphurous acid and ether 
in the form of a yellow liquid, from which it may be separated 
by means of lime and sulphuric acid. 

Q. What properties characterize the oil of wine? 

A. It is a transparent, nearly colourless, unctuous substance, 
very fragrant, and having a taste resembling that of peppermint. 

Gt. What is Hoffman's Anodyne Liquor '? 

A. It is alcohol containing the oil of wine and common ether. 

OF ALCOHOL OR THE HYDRATED OXIDE OF 
ETHYL. 

Q. What is alcohol ? • 

A. It is the intoxicating ingredient in vinous liquors, and is 
the result of the vinous fermentation. 

QL. How is alcohol obtained 1 

A. It is separated from fermented liquors by distillation, in 
consequence of its boiling at a lower temperature than water. 
To produce the purest alcohol, pearl ash or lime is used to 
attract moisture, and then subjected to re-distillation. 

Q,. What conditions are required for the process of the vinous 
fermentation ? 

A. The presence of sugar, water, and yeast at a temperature 
between 50 and 120 degrees of F. 

Gl. How is the conversion of sugar into alcohol explained ? 

A. Sugar consists of oxygen, hydrogen, and carbon in equal 
proportions. In consequence of the evolution of one atom of 
carbon with two atoms of oxygen as carbonic acid, during the 
process of fermentation; there remain three atoms of hydrogen, 
two atoms of carbon, and one of oxygen, from the decomposi- 
tion of three atoms of sugar which are required to be present : 
and these are the atomic proportions, constituting alcohol. Or 
to assume the following explanation; viz., one atom of dry grape 
sugar, represented by the formula C^2 H12 0^2^ is converted into 
two atoms of alcohol and four atoms of carbonic acid, thus : 



140 CATECHISM ON CHEMISTRY. 

Two atoms of alcohol C 8 H12 Q 4 

with four atoms of carbonic acid C ^ O ^ 



forms one atom of sugar 0^2 H^^ 012 

Q. What are the properties of alcohol? 

A. It is a colourless fluid, of a penetrating- odour, burning 
taste, is volatile, inflammable, has a less capacity for heat than 
water, boils at 176 degrees, and is said never to have been 
frozen. The specific gravity is near 800. Alcohol unites with 
water producing a rise of temperature, and by combustion, 
yields water and carbonic acid; and when passed through a red 
hot porcelain or copper tube, it is decomposed into water and 
carburettedJij'droo^en. 

Gl. What is nitric or nitrous ether ? 

A. It may be regarded as a compound ether, being the hy- 
ponitrite of the oxide of ethyl or nitrite of ethyl. 

Q,. How is it obtained '? 

B. By distilling alcohol with dilute nitric acid, taking care 
that the reaction be not too violent. 

Gl. What is the rationale? 

A. From an atom of the acid employed, two atoms of oxygen 
uniting with two atoms of hydrogen of an atom of alcohol, 
convert it into aldehyde. Meanwhile, three atoms of oxygen, 
remaining in union with one of nitrogen, in the state of hyponi- 
trous acid, combine with an atom of the oxide of ethyl expell- 
ing the water, by which it existed as alcohol. Hence it follows 
that one-half of the alcohol must have been destroyed. — Hare. 

Gl. Wha^ is sweet spirits of nitre ? 

A. It is a solution of hjponitrous ether in alcohol, obtained 
by subjecting nitre and sulphuric acid to distillation with an 
excess of alcohol. 

a. What is aldheyde ? 

A. It is the hydrated oxide of acetyl, formed when we de- 
prive alcohol of two atoms of hydrogen, and is one of the pro- 
ducts of the decomposition of alcohol or ether by passage 
through a red hot tube, and is also generated during etherifi- 
cation by nitric acid, &c. 



CATECHISM ON CHEMISTRY. 141 

Q.. What are the properties o^ aldehyde 7 

A. It is a colourless, inflammable liquid, of a peculiar ethe- 
rial and suffocating odour, soluble in water, alcohol and ether ; 
and by absorbing atmospheric oxygen, it is converted sponta- 
neously into acetic acid. 

Q. What is methylic ether ? 

A. It is the oxide of methyl, obtained by distilling wood 
spirit with sulphuric acid. 

Ql, What are the properties of the oxide of methyl ? 

A. It is an inflammable, colourless gas, of an agreeable 
etherial odour, having the formula of C^ H^ O. 

Gt. What is pyroxylie or wood spirit ? 

A. It is the hydrated oxide of methyl, obtained in the distil- 
lation of acetic acid from wood. 

Q,. What are the properties of pyroxilic spirit 1 

A. It is a volatile, colourless liquid, its taste and odour being 
intermediate to acetic ether and alcohol, is very inflammable, 
and burns with a pale flame. 

Q. What is amylic alcohol ? 

A. It is the hydrated oxide of arayl, called oil of potato 
spirit, generated during the vinous fermentation of an infusion 
of potatoes. 

Q. What propeaties characterize potato spirit 1 

A. It is a coioarless liquid, oily in appearance, very strong 
smell, first pleasant, but becoming very nauseous, of an acrid 
taste, burning with a bluish flame. 



ANIMAL CHEMISTRY. 

Q.. What are the ultimate elements of animal matter ? 

A. Oxygen, hydrogen, nitrogen, and carbon. Besides these 
animal substances are found to contain sulphur, phosphorus, 
calcium, small portions of iron, &c. 

Gl. W^hat are some of the remote organic elements or proxi- 
mate principles in animal matter ? 



142 CATECHISM ON CHEMISTRY. 

A. Proteine, and its modifications, such as albumen, fibrin, 
and casein, also gelatin. 

Q,. What is proteine ? 

A. It is a compound radical, existing in animal matter, ob- 
tained by digesting albumen, fibrin, or caseine in a hot solu- 
tion of caustic potash, precipitating by means of acetic acid, 
and washing and drying the precipitate. 

Cl. What properties characterize proteine 1 

A. It is a yellowish brittle mass, insoluble in water and 
alcohol, and capable of combining with both acids and bases. 
The composition of proteine is represented by C^s H^s N^ O^^. 

Cl. Where is albumen found '? 

A. In the serum of the blood, in certain vegetable juices," 
and in the animal solids, and it constitutes the white of eggs. 

d. What are the properties of albumen '? 

A. It may be described as existing in two states, the liquid 
or soluble, and the coagulated or solid albumen. Liquid albu- 
men is soluble in water and insoluble in alcohol, and is coagu- 
lated by heat, alcohol, and the acids. Solid albumen is insoluble 
in water but soluble in alkalies, from which it may be precipi- 
tated by acids, to wljich the acetic and phosphoric are excep- 
tions. Muriate of tin, acetate of lead, bichloride of mercury, 
and infusion of galls all precipitate albumen. It is the best 
test and antidote for corrosive sublimate. 

Q. Where is fibrin found % 

A. It exists in a fluid state in the blood, and in some vegeta- 
ble juices; and in a coagulated state in the gluten of wheat 
flour, and in muscular fibre. 

d. What properties distinguish fibrin ? 

A. Like albumen it exists in both a fluid and solid state; 
and like it, is coagulated by heat and acids, and is soluble in 
alkaline solutions. In the solid state it is white, insipid, inodor- 
ous, insoluble in cold, but slightly soluble in boiling water ; 
also soluble in concentrated sulphuric acid ; and it gives a 
purple colour when it is mixed with strong chlorohydric acid. 



CATECHISM ON CHEMISTRY. 143 

Q. What does it contain ? 

A. In addition to proteine, it contains, like albumen, sulphur, 
phosphorus and lime, only that it contains less sulphur. 

Gl. What changes are effected by incubation and digestion'? 

A. By incubation albumen passes into fibrin, and fibrin, in 
the animal body, is converted into albumen. 

Q,. Is fibrin an element of nutrition? 

A. Yes. Very important, and yields, in the animal body, 
albumen, and caseine, and the tissues derived from them. 

Gl. Where does caseine exist 1 

A. In milk. Cheese made from skimmed milk, and well 
pressed is nearly pure caseine. Legumine^ a substance existing 
in the seeds of leguminous plants, is identical with caseine. 

Gl. What properties distinguish caseine'? 

A. When dry, it is like gum, not readily soluble in water, 
never forming a clear solution, and precipitated by acetic acid, 
and distinguished from albumen in being coagulated only by 
acids, and not by heat. 

Gl, Is coagulated caseine simply caseine? 

A. No. It is generally a compound of caseine with the acid 
employed to coagulate it. 

Gl. What causes the spontaneous coagulation of milk 7 

A. The presence of free lactic acid, generated by a species of 
fermentation, which combines with the caseine as a lactate. 

Gl. How is the coagulation of milk by rennet explained ? 

A. The mucous membrane of a calf's stomach (rennet), being 
in a state of decomposition, acts as a ferment. 

Gl. Is caseine capable of being converted into albumen and 
fibrin, and vice versa ? 

A. Yes. The utility of milk in the nutrition of young 
animals, proves that caseine can be converted into albumen 
and fibrin, and the reverse is proved by the production of milk 
in an animal fed on these substances. 

Gl. How do albumen, fibrin, and caseine differ in composition? 

A. Albumen, in losing half its sulphur, becomes fibrin, and 
fibrin, in losing its phosphorus, becomes caseine. 



144 CATECHISM ON CHEMISTRY. 



BLOOD. 



Gl. Into what two portions is the blood divided ? 

A. Into the serum, and crassamentum or coagulum. 
d. Of what is the coagulum of the blood composed 1 

A. Of fibrin, and of two compounds called hcemalosine and 
globuline. 

Gt. What is said of heematosine ^ 

A. It is the substance to which the colour of the blood has 
been attributed, and contains iron. It is insoluble in water, 
alcohol, and in ether. And forms red solutions with alcohol, ta 
which either alkalies or acids are added. 

a. What is globulin'? 

A. It is that which forms the principal part of the globules 
of the blood. In its pure state, it resembles albumen in charac-- 
ter and composition. 

Gl. What does the sernm of the blood contain ? 

A. Albumen, contained in a liquid composed of water, some 
salts, &c., which liquid is called serosity. 

Q,. What is the analytical composition of blood? 

A. Water, fibrin, hsematosine, globuline, albumen, fat, oily 
matter, extractive matter, alkaline salts, magnesia and iron. 

Gl. On what is the colour of the blood dependent 1 

A. It has been erroneously attributed to the presence of iron, 
as the blood has been deprived of this principle without de- 
stroying the colour. It is not determined. 

Gl. Of what is muscular tissue composed ? 

A. Fibrin, blood, nervous matter, &c. 

Gl. What is osmazome? 

A. A substance which is dissolved by the action of hot water 
upon flesh, and which gives to soap and dressed meat its pecu- 
liar flavour. It is a substance of which but little is known. 

Gl Where is gelatin found ? 

A. In the solid parts of the body, as in bone, tendon, liga- 
ment, serous membrane, skin, &c. 



CATECHISM ON CHEMISTRY. 145 

Q,. How is gelatin obtained ? 

A. By boiling- for a long time in water, substances that con- 
tain it, and evaporating the solution. 
CI. What are the properties of gelatin 1 
A. It is solid, tasteless, colourless, soluble in water, (forming 
jellies on cooling) and in dilute acids ; but insoluble in alco- 
hol, ether, and the oils, precipitated by tannic acid, forming 
with it an insoluble substance analogous to leather. 

Q. How is leather made ? 

A. By steeping softened skins in a strong infusion of oak 
bark, catechu, and other substances containing tannic acid. 

Gl. What is the composition of gelatin? 

A. Its formula is represented by the elements of 2 atoms of 
proteine, 3 atoms of ammonia, 1 of water, and 7 of oxygen. 
Nearly related as gelatine is to proteine, yet it contains none 
of that radical. 

Q. Is gelatin capable of supporting animal life ? 

A. No. As it contains no proteine, it cannot be converted 
into albumen, fibrin, or caseine, consequently it cannot form 
blood.* # 

Q,, Why is gelatin serviceable as a diet for convalescents ? 

A. Because the debilitated system cannot readily convert 
albumen into gelatin, in sufficient quantity, to nourish the ge- 
latinous tissues. 

Q. What is glue^ sise, and isinglass, and how do they differ? 

A. They are all different forms of gelatin; glue is formed 
from the coarser forms of gelatin, as hoofs, hides, &c.; sise 
from the skin and fine membranes ; and isinglass, which is the 
purest gelatin, is formed from the air bladder and other mem- 
branes offish. 

Gl. Whdit is cJiondrine? 

A. It is a substance resembling glue, from which it differs 
in not being precipitated by tannic acid ; it forms the tissues 
in the cartilage, trachea, nose, &c. 

Q. What is the composition of the brain and nervous system? 
13 



146 CATECHISM ON CHEMISTRY. 

A. It is intermediate in its composition between fat and the 
compounds of proteine, containing more carbon than proteine, 
and less nitrogen, and in containing some phosphorus. 

d. What proximate principles does nervous matter contain ? 

A. Cerebric, oleo-phosphoriCy oleic , and margaric acids^ also 
a peculiar fat called cholesterine. 

Q,. What is the composition of bones? 

A. Phosphate of lime, gelatin, carbonate and fluate of liraey 
&c. 

Q. In what do teeth differ from bones % 

A. In containing a greater proportion of earthy matter. 
The enamel contains fluoride of calcium, but no animal matter. 

x\NIMAL SECRETIONS. 

Q. What is the analysis of milk ? 

A. Cheese or caseine, butter, sugar of milk, salts, albuminous 
matter, and water. 

Gl. Is milk capable of supporting animal life 1 

A. Yes. The casein^and albumen serve for the formation 
of blood, the sugar and fat support respiration, and the salts that 
are necessary for the human system are furnished. 

Q,. Of what is the saliva composed ? 

A. Water, and about 1 per cent of a solid saline matter. 

Q,. What is pepsine ? 

A. It is a peculiar matter, constituting the active principle 
of the gastric juice, obtained by the infusion of the mucous 
membrane of the stomach in acidulated water, and also formed 
in the stomach during the fermentation, produced by the pre- 
sence of organic matter in a state of decomposition. 

Q,. What are the properties of the gastric juice '? 

A. In the empty stomach, it is neutral, but during digestion 
it becomes acid, owing to the evolution of chlorohydric acid. 

d. In what does the pancreatic juice differ from the saliva '? 

A. In being acid, and in containing albumen and caseine. 



CATECHISM ON CHEMISTRY. 147 

Q. What enters into the composition of bile? 

A. Bile has been found to contain choloic, choloidic, cholic, 
fellinic, and cholinic acids, and biline, biliverdine, dyslysine, 
taurine, soda, &c. And biliary calculi has been found to con- 
tain lithofellic acid, 

Q,. What is lymph ? 

A. It is a watery fluid containing^ a small trace of albumen 
and common salt, coagulated by heat and nitric acid, and is 
secreted from cellular membranes. 

Q,. What is mucus 1 

A. It is a secretion from mucous membranes, insoluble in 
water, but which swells with it, like tragacanth, into a viscid 
mass. 

a. What is pws ? 

A. It is a secretion from ulcerated surfaces. When healthy, 
it is a thick yellowish liquid, formed of opaque globules floating 
in a clear fluid. When mixed with water, the globules fall, 
forming a yellow, insoluble sediment. Pus contains albuminous 
matter, fatty matter, and salts, and is coagulated by heat and 
acids. 

d. How may we distinguish between mucus and pus ? 

A. By the action of caustic potash pus becomes thick, while 
the mucus forms with it a thin solution. 

Q. What are the principle characteristic proximate elements 
in urine '? 

A. Urea and uric acid are the most important. 

Gt. How is urea obtained ? 

A. By mingling together an aqueous solution of the cyanate 
of potash and sulphate of ammonia, and subjecting the aggre- 
gate to boiling alcohol which takes up the urea only. On cool- 
ing the urea crystallizes. 

Gl. What are the properties of urea 7 

A. It is a solid, having four sided prismatic crystals, soluble 
in water and in alcohol, and having a taste resembling nitre. 

Q.. What does the analysis of Berzelius prove the human 
urine to consist of? 



148 CATECHISiVI ON CHExMISTRY. 

A. Water, urea, uric acid, lactic acid, lactate of ammonia, 
and animal matter adhering to them, mucus of the bladder, the 
salts of the alkalies, earthy matter, fluoride of calcium, and 
siliceous earth. 

Gt. What are the varieties of urinary calculi 1 

A. These are uric acid^ urate of ammonia^ bone earthy am- 
moniaco-magnesian phosphate^ fusible calculus, oxalate of lime 
or mulberry calculus^ xantldc oxide^ and cystic oxide. 

Gt. Are these different calculi equally abundant 7 

A. No. Xanthic oxide, and cystic oxide are of very rare 
occurrence, while the ammoniaco-magnesian phosphate, bone 
earth, and fusible calculus, (which is composed of the tvt^o last,) 
are of very frequent occurrence, but the most abundant of all 
are those of uric acid. 

Gl. How do we distinguish those of uric acidl 

A. They have generally a fawn colour, are soluble in caustic 
potash, from which they may be precipitated by acids, and 
soluble in nitric acid aided by heat ; and the solution, when 
gently evaporated to dryness, leaves a purple stain of murexide. 
And they are totally consumed before the blow-pipe. 

Gt. How is the bone earth distinguished'? 

A. They have a fawn colour like the uric acid calculus, 
from which they may be distinguished by giving out ammonia 
when they are digested with potash. 

Q,. How is the ammoniaco-magnesian phosphate calculi dis- 
tinguished ? 

A. By its solubility in acetic acid, and being precipitated by 
ammonia. When heated it gives off ammonia, and leaves be- 
hind phosphate of magnesia. 

Ql. How is fusible calculi distinguished ? 

A. In being white and chalky, very fusible, and by part 
being soluble in acetic acid and the rest in chlorohydric acid. 

Gt. How is mulberry calculus distinguished ? 

A. By being very hard, dark coloured and rough, insoluble 
in acetic acid, and when heated to redness converted into car- 
bonate of lime. 



CATECHISM ON CHEMISTRY. 149 

Q. How is xanthic oxide and cystic oxide distinguished "l 

A. The first is a light brown colour, becoming resinous by 
friction, and soluble in caustic potash, from which it is pre- 
cipitated by carbonic acid; the second is of a yellowish white 
colour, crystalline, with a waxy lustre, soluble in caustic potash, 
ammonia, and in the mineral acids. Both of these calculi are 
consumed before the blow-pipe. 

Q. What is the nutritive principle of animal life ? 

A. Proteine or its modifications, albumen, fibrin and caseine. 

Gt. In what does the life of animals and vegetables chemi- 
cally differ ? 

A. In animals oxygen is constantly absorbed and replaced 
by carbonic acid, While in vegetables carbonic acid is absorbed, 
its carbon being retained and its oxygen given out. 

Q. In what does the phenomena of respiration consist? 

A. In the decarbonization or oxygenation of the blood as it 
passes through the lungs; it is a chemico-vital process. 

Q,. What is fermentation ? 

A. Certain spontaneous changes which ensue in organic 
substances whereby they form new combinations. 

Q. What are different kinds of fermention 1 

A. The saccharine, the vinous, the viscous, the acetous, and 
what is called putrefaction. 

Q,. What does the saccharine consist in ? 

A. The conversion of the starch of grain into grape sugar. It 
is that which takes place in the wash of the distillery. The 
starch takes two atoms of water. 

Q. What is the vinous fermentation ? 

A. It is the process by which the sugar existing in juices of 
the grape and other fruits, is converted into alcohol and car- 
bonic acid. An atom of grape sugar is hereby converted into 
two atoms of alcohol and four of carbonic acid. 

Q. In what respect does the vinous fermentation of the 
juice of fruits differ from that of barley ? 

A. In the juices there is a natural ferment, but in the case 
13* 



150 CATECHISrvI ON CHEMISTRY. 

of wort, as prepared in breweries, there is required an artificial 
ferment, as yeast, and the starch of barley necessarily passes 
through the saccharine fermentation, and becomes sugar to en- 
able it to undergo the vinous. 

Q. Is cane sugar, as such, capable of the vinous fermenta- 
tion ? 

A. No. It must first become grape sugar, 
Q. What is the acetous fermentation 1 
A. It is the process by which fermented or spiritous liquors 
are converted into acetic acid, or vinegar. 

Q. What change does this fermentation consist in? 
A. The conversion of ethyl into acety]. This process requires 
an extraneous supply of oxygen, and by the oxidation of two 
proportions of hydrogen, and then by the addition of three 
more atoms of water, we have a hydrated tritoxide of acetyl 
or vinegar. 
Gl. Will dilute alcohol ferment per se 1 
A. No. It requires some substance to attract oxygen from 
the air at a proper temperature. 

Q. What is the lactic or viscous fermentation ^ 
A. It is that vvhich supervenes in the absence of yeast, and 
differs from the vinous in giving rise to lactic acid, mannite 
and a ropy matter, with hydrogen and carbonic acid. 
Q. What excites this action ? 

A. Lactin, oxidized casein, diastase after exposure to the air, 
the membranes of the stomach of the dog or calf, or the sub- 
stance of a bladder and the bile. 

Q. Does each kind of fermentation require its peculiar fer- 
ment ? 

A. Yes. Diastase incites the saccharine fermentation, 
yeast the vinous, oxidized diastase, casein or curd the lactic^ 
while the mother of vinegar promotes the acetic fermentation. 
Q. What is the putrefactive fermentation ? 
A. It is the spontaneous decomposition, which animal sub- 
stances in particular undergo, when from under the control of 
vital laws. 



CATECHISM ON CHEMISTRY. 151 

Q. Why is animal putrefaction more offensive than vegetable? 

A. Because of the presence of phosphorus and sulphur in 
animal matter. 

Q. Will fermentation go on in substances perfectly dry ? 

A. No. The presence of water is indispensable to the spon- 
taneous decomposition of organic substances. 

Q. Why is it that a high temperature as well as frost arrests 
putrefaction ? 

A. Because in the one case the w^ater is vapourized, in the 
other congealed. 

Q. What are the products of putrefaction ? 

A. Water, ammonia, carbonic and acetic acid, sulphydric 
acid, carburetted hydrogen, and sometimes phosphuretted hy- 
drogen. 



END OF ORGANIC CHEMISTRY. 



152 CATECHISM ON CHEMISTRY. 



ELECTRICITY. 

Q. What is electricity defined to be ? 

A. The unknown cause of the attractive power which certain 
substances acquire by friction. 

Q. How early was this discovery made ? 

A. Six hundred years before Christ, when it attracted the at- 
tention of Thales. 

Q. What is the term electricity derived from'? 

A. The Greek word (electron) signifying amber, the sub- 
stance in which this power was first noticed. 

Q. When was any additional discovery made ? 

A. In the seventeenth century Otho Guericke observed that 
light and sound might be the effect of electrical excitement. 

Q. How is electricity excited ? 

A. By mechanical and chemical means. Mechanical elec- 
tricity is produced by subjecting certain' substances to friction 
and pressure; galvanism is electricity evolved by chemical 
agency. Substances excited by mechanical means are called 
electrics. 

Q.. What substances are electrics ? 

A. Amber, glass, resins, &c. 

Gl. Can the electric virtue pass from one part of an electric 
which is excited, to another ? 

A. It cannot without extraneous aid ; hence electrics are 
non-conductors, 

Q. What substances are conductors of electricity ? 

A. Metals, charcoal, flax or hemp, and water. The metals 
are the only perfect conductors, though they are not equally 
good. Next to metals charcoal is the best. 

Q. Are conductors electrics ? 

A. No. Because they convey off the electric virtue. Elec- 
trics are non-conductors, and conductors are non-electrics. Sul- 
phur, resin, glass, silk and wool are non-conductors. 



CATECHISM ON CHEMISTRY. 153 

Q. Can a conductor be excited ? 

A. It can, provided it be supported upon a non-conductor; 
that is, insulated. 

Q. What was the theory of Du Faye ? 

A. That there were two electrical fluids, one kind excited 
by rubbing glass, called vitreous, the other excited by rubbing 
resin, called resinous electricity. When either kind of excite- 
ment was communicated to light bodies, they were made to 
separate from each other, but the bodies excited by means of 
glass were attracted by such as were excited by means of resin* 

Q.. What did Franklin ascertain to happen when either kind 
of electricity is communicated to a body by friction ? 

A. That the opposite kind was created in the mass by means 
of which that friction is affected, provided it be insulated. For 
instance, when a glass tube is rubbed by an insulated cushion, 
the former will be vitreously excited, the latter resinously; but 
if a stick of resin be substituted for the glass, the latter will be 
resinously excited, and the cushion vitreously. 

Gl. What was Franklin's theory of electricity ? 

A. That there is but one electric fluid — to different states of 
which the names of vitreous and resinous electricity had been 
applied erroneously. The latter he called negative, the former 
positive electricity. 

Gt. How did he account for the fact that when either kind 
of electricity is communicated to a body by friction, the oppo- 
site kind will be excited in the rubber, provided both be insu- 
lated ? 

A. That some bodies, by friction, acquire additional power 
to hold the electric fluid, and hence draw it from the conduct- 
ing body rubbing them ; others have their capacity for this fluid 
diminished by the same means, and hence give it out to the 
rubber. Glass, for instance, becomes redundantly, and rcsiu 
deficiently excited by friction. 

Gl. When glass is rubbed by the hand what happens ? 

A. It takes electricity from the hand and the person to whom 
it belongs. 



154 CATECHISM ON CHEMISTRY. 

Q,. Suppose the person be insulated 1 

A. He would be negatively electrified ; that is, the glass 
would be positively electrified at his expense, as the communi- 
cation with the earth is cut oif by insultation, whence the 
electricity was derived. 

Gl. Suppose the glass be in contact with another body? 

A. The body will be excited vitreously or positively. 

Q,. Suppose a stick of resin be substituted for the glass 1 

A. Vitreous electricity will be excited in the person, and re- 
sinous in the body touching the resin. 

Gl. How did Franklin identify lightning with electricity ? 

A. By drawing this fluid from the clouds by means of a kite. 

Q,' What is necessary to form an electrical machine 1 

A. An electric situated so as to be subjected to friction, one 
or more collectors attached to a prime conductor, properly in- 
sulated, and one or more cushions for rubbing the electric. 

Q,. What happens when the two conductors of a machine in 
operation are made to communicate by means of a perfect con- 
ductor 7 

A. An electric circuit is formed. In this case all excitement 
ceases; proving that the redundancy in the positive is equal to 
the deficiency in the negative conductor. 

Q. What are the poles defined to be ? 

A. Those parts of the circuit through which sparks pass; or 
that point of an electric, galvanic, or voltaic circuit, at which 
ignition, light, chemical decomposition, or sensation, are per- 
ceived. 

Q. What happens if any perfect conductor be in connection 
with either pole ? 

A. It assumes the same electrical state as the pole, and trans- 
fers the polar influence to the other end of the conducting rod 
or wire. 

Q. What happens when either side of a pane of glass is 
charged ? 

A. The other side will acquire a charge of the opposite na- 



CATECHISM ON CHEMISTRY. 155 

lure. That is, a stream will be ^iven off as tlie opposite side is 
vitreously excited. 

Q. When was the Leyden phial invented ? 

A. In the year 1746, by Cuneus and Mushenbroeck. 

d. Does the electricity of the Leyden jar reside in the coat- 
ing? 

A. No. By removing the coating* it will be found in the 

glass. 

Q. What is the use of the coating ? ^ 

A. In order that every point of the glass on both sides may 
be brought into communication at the same moment. 

Q. What is the electrical battery ? 

A. A number of Leyden jars with a communication between 
their interior coatings. 

Q. What is meant by the terra of electricity by induction ? 

A. It is the electric state of a body, which is induced by con- 
tiguity with an electrified body without contact — or where one 
surface being in contact with an excited conductor, a tendency 
is induced in the electricity, on the other side of the electric, to 
leave it. 

Q. What happens when one surface of a pane of glass is in 
contact with the negative pole in a state of insulation ? 

A. Electricity is abstracted from the surface in contact 
with the pole, while the other surface is positively excited at 
the expense of any other body with which it may be in contact. 
Illustrated by a series of panes of glass, coated with tin foil, in 
communication with each other and the poles. 

Q. What means are there for detecting or measuring elec- 
tricity ? 

A. By estimating the degree of attraction which light bodies 
undergo by means of instruments called electrometers. 

Q. What are the effects of electricity ? 

A. The attraction or repulsion of electrified bodies, the ex- 
trication of light and heat, and the shock given to the human 
frame. 



155 CATECHISM ON CHExMISTRY. 

Q. Why is it that two bodies, similarly electrified, repel each 
other ? 

A. According to the Franklinian doctrine, it is in reality the 
effect of an attraction between them and the matter of the ad- 
joining* medium. It is for the same cause that attraction takes 
place between bodies differently excited, that they are repelled 
when similarly electrified. 

Q, How is it explained on the theory of two fluids ? 

A. That the particles of either kind are self repellent. 

Q. How is the phenomenon of electrical light illustrated? 

A. By having one side of the coated pane left with minute 
interstices between the tin foil. 

Q. Is there a diversity in the appearance of the electric 
spark? 

A. Yes. There is the short straight, and the long zigzag 
spark. 

Q. What causes the zigzag shape of the spark ? 

A. By the condensation of the air before it, it is obliged to 
change its direction; and the large surface to which it is di- 
rected offers no point of attraction, consequently its course 
changes. 

Cl. What substances are ignited by the electric spark ? 

A. Cotton, ^ther and other combustibles, and hydrogen will 
explode with oxygen, when mingled in certain proportions. 

Q. How is a patient electrified ? 

A. By placing him on an insulated chair, and in communi- 
cation with one of the conductors. Being thus negatively or 
positively electrified, sparks may be taken from any part of the 
body by a metallic knob or point. 

Q. What effect have small points in receiving the electric 
virtue? 

A. The effects of electricty are so mitigated by them that 
what would produce a shock through a knob, is insensibly re- 
ceived. Hence the use of pointed rods, as a protection against 
lightning. 



CATECHISM ON CHEMISTRY. 157 

Q. What cautions are necessary in constructing and putting 
up lightning rods? 

A. Its points should be made of platina or other infusible 
metal; its joints perfect, and its termination with a metallic 
surface under the earth, or other conducting matter. 

GALVANIC ELECTRICITY. 

Q. What was the first galvanic observation made ? 

A. That a peculiar taste v^'as produced when the projecting 
ends of two metals, one being placed above, the other beneath 
the tongue, were brought in contact. 

Q. Are all metals equally capable of producing this effect? 

A. No. It depends on their diversity of oxidization. 

Q. What did Galvani subsequently ascertain ? 

A. That by the same means convulsions were produced in 
frogs. 

Q,. How did philosophers account for this fact? 

A. By erroneously supposing the nerves and muscles of the 
animal to be in opposite electrical states, which were neu- 
tralized by the conducting power of the metals. Volta detected 
this error, by demonstrating that these effects resulted from the 
metals on the animal, and not the animal on the metals. 

Q,. What is the galvanic pair ? 

A. It consists of two metals, possessing different powers of 
oxidization ; or several disks may constitute a pair, provided 
the surfaces of the same be in communication. 

Q. Are the form and size of the plates material ? 

A. No. But it is necessary that they be near and parallel to 
each other. 

Q. What composed Volta's pile? 

A. Disks of copper and zinc, alternated with each other and 
with pieces of moistened cloth, which separated them into pairs, 
consisting of one disk of each metal. On touching simultane- 
ously the extremities or poles, a shock was experienced. 
14 



lo8 CATECHISM ON CHE3IISTRY. 

Q. What was the disadvantage of the Voltaic construction ? 

A. The supply of moisture was inadequate. 

Q. What was theCouronne des Tasses ? 

A. Disks of copper and zinc, soldered to arches of wire, so 
as to be consecutively immersed in adjoining tumblers, in the 
same alternate order as in the Voltaic pile. This was invented 
to obviate the want of moisture in the Voltaic pile. 

Q. What was Cruickshank's contrivance? 

A. He made plates of zinc and copper, soldered face to face, 
to serve as partitions in a trough. Another construction was 
contrived by Dr. Babington, consisting of a porcelain trough 
with cells, resembling Cruickshank's trough, but the metallic 
plates were united by arches of metal so arranged as to be im- 
mersed in the acid, and lifted out at pleasure. 

Q. What is the most improved construction ? 

A. Cruickshank's trough, so modified as to allow the acid to 
be thrown on or off the plates instantaneously. 

Q. What is the difference between an electrometer and a 
calorimeter ? 

A. The capacity of setting electricity in motion, or the quan- 
tity and intensity it produces, is dependent on the number of 
pairs in the galvanic series ; but when arranged in large pairs, 
its calorific influence is superior. 

Q,. What was the galvanic theory of Volta ? 

A. That the contact of dissimilar metals, or their communi- 
cation through perfect conductors, is the source of galvanic ex- 
citement. This doctrine is objectionable, because no ignition 
is produced until the plates are immersed. 

Q. What was the theory of Wollaston ? 

A. That the chemical action, which consists in the oxidation 
of the zinc, is the primary cause of the galvanic excitement. 
As a confirmation of this doctrine, it was observed, that no sen- 
sible effect was produced by a combination of condactors which 
do not act chemically on each other; and that the energy of 
the pile was in proportion to the corrosion of the metallic plates. 



CATECHISM ON CHEMISTRY. 159 

Q. What theory was suggested by Sir Humphrey Davy 1 

A. That while on the one hand, the contact of two metals of 
different affinities for oxygen is capable of disturbing the elec- 
trical equilibrium, so on the other, it is equally true, that the 
chemical changes contribute to the result, without which the 
excitement can neither be considerable in degree, nor of long 
duration ; that is to say, the action is begun by the contact of 
the metals, and kept up by chemical action. 

Q,. What is a simple galvanic circle ? 

A. When the two plates, immersed in a liquid, are made to 
communicate, either by contact or by conducting wires. The 
electricity generated on the surface of the zinc, in contact with 
the fluid, renders the zinc plate positive, and the copper nega- 
tive. The current is thus directed from the zinc, through the 
fluid to the copper, and from the copper along the wire to the 
zinc again. 

Q. When the conducting wire is interrupted, which forms 
the positive pole? 

A. That connected with the copper plate. As the plate of 
zinc is rendered positive at the expense of the wire attached to 
it, so the latter forms the negative pole. 

Gl. What are the effects of galvanism ? 

Gt. It is capable of producing caloric, light and electricity, 
as coordinate products, chemical decomposition, and it exerts 
a peculiar action on the magnet. 

Gl. What is an example of its producing chemical action ? 

A. The decomposition of water, by means of the wires of the 
two poles when immersed in that liquid. The oxygen goes to 
the positive, and the hydrogen to the negative pole. 

Q. What effect has galvanism on magnetism ? 

A. It communicates the magnetic virtue to iron, steel, &.c. 

ELECTRO-MAGNETISM. 

CI. What analogy is there between electricity and magnet- 



160 CATECHISM ON CHEMISTRY. 

A. That similar poles of a magnet freely suspended recede ^ 
from each other, and dissimilar poles approach to each other. 
But electricity and magnetism cannot be identical, as the mag- 
netic needles being perfect conductors of the former fluid, both 
extremities would be in the same electrical state. 

Q,. What peculiar effect is produced by the galvanic current 
on the magnetic needle ? 

A. When the current passes near the needle the latter as- 
sumes a contrary direction. This fact is accounted for or] the 
theory, that when a galvanic current is directed in a right line 
the magnetic current will revolve around that line, like the cir- 
cumference of a wheel around its own axis. 

CL. Can electricity be produced by the magnetic current ? 

A. Yes. Faraday found that a magnetized iron bar may^ 
by alternate introduction, and withdrawing from a coil of wire, 
produce electrical currents, called Faradin currents. 



LBJL'iS 



